JPS63172480A - Magnetic flux quantum element - Google Patents

Abstract

PURPOSE:To eliminate the need for S branch structure, and to control the propagation of a magnetic flux quantum by connecting an output terminal for a first Josephson line and an input terminal for a second Josephson line by a resistor, using an input terminal for a third Josephson line as the magnetic flux quantum for control and forming a superconducting loop. CONSTITUTION:When a magnetic flux quantum for control is propagated from an input terminal 30a for a third Josephson line 30, the magnetic flux quantum is stopped and held in an inductance loop between an output terminal 30b and a second Josephson line 20. When the magnetic flux quantum is input to an input terminal 10a for a first Josephson line 10, the magnetic flux quantum is input to the second Josephson line 20 through a resistor 5. When the magnetic flux quantum for control is not held, the magnetic flux quantum being propagated on the first Josephson line 10 is discharged to the outside from a resistor 5 section, and the magnetic flux quantum propagated on the second Josephson line 20 and the magnetic flux quantum propagated to the third Josephson line 30 side are formed from the magnetic flux quantum input to the second Josephson line 20.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to a method for controlling the propagation of magnetic flux quanta (called a Josephson portex) in a Josephson line by other magnetic flux quanta. It is applied to quantum devices, such as high-speed logic circuits and memories.

(Prior Art) As a conventional element for controlling the propagation of magnetic flux parent and child in a Josephson line using other magnetic flux quanta, there is, for example, a magnetic flux ω element insertion gate (F■ gate) as shown in FIG. 1985 IEICE Technical Report 5CE85-52).

In FIG. 9, 1 is a first Josephson line, 2 is a second Josephson line, 3 is a third Josephson line, and 4 is a fourth Josephson line. Each Josephson line is
Taking the first Josephson line 1 as an example, it has a laminated layer llTi with a tunnel barrier 13 sandwiched between an upper electrode 11 and a lower electrode 12 made of a superconductor, and the upper electrode 11 has this laminated structure. A bias current line 44 for supplying bias current 1b is connected to the Josephson junction consisting of the following.

In addition, the first, second, and third Josephson lines 1.2.3
The lower electrodes 12, 22, and 32 are commonly grounded to a ground plane (not shown) made of a superconductor. Therefore, in FIG. 9, the lower type if! of both the first and second Josephson lines 1.2 is shown. 12.22 are depicted as being connected to each other by a superconductor 48, but even if there is no such connection indication, each of the first, second, and third Josephson lines 1.2. The lower electrode 12.22.32 of 3 is
By grounding to the Guérande Brage, they are commonly connected via the superconductor that constitutes this ground plane.

The same goes for the following figures as well, in which the parts shown as grounded are connected via the superconductor.

Among the four Josephson lines, the lower electrode 42 of the fourth Josephson line 4 is not grounded, but is connected to the upper electrode 21 of the second Josephson line 2 at its input end 4a side. The second Josephson line 2 and the fourth Josephson line 4 are vertically branched into a V-shape as shown.

Further, each upper electrode 11.4 of the output end 1b of the first Josephson line 1 and the input end 4a of the fourth Josephson line 4
The upper electrodes 31.21 of the output end 3b of the third Josephson line 3 and the input end 2a of the second Josephson line 2 are connected by superconductors 49.51, respectively. .

Here, the S-branch and T-branch structures, which are known as the branch structure of the Josephson line, are shown in (A) and (A) in Figure 10.
B) and FIG. 11.

First, in the S branch, as shown in FIG. track 52
the upper electrode of the second line 53 and the upper electrode of the first line 5
2, the lower electrode of the third line 54, and the second line 54.
The lower electrode of the line 53 and the upper electrode of the third line 54 are connected to each other.

In a specific element structure formed in an IC process, the S branch is configured as shown in FIG. 10(B).

That is, the lower electrode of the first line 52 and the lower electrode of the third line 54 are formed by a common lower electrode 55, and a tunnel barrier 5 formed of one plane is formed on the common lower electrode 55.
2a and 54a are formed. Tunnel barrier 54a
A common electrode 1m56, which serves as the lower electrode of the second line 53 and the upper electrode of the third line 54, is formed above. A tunnel barrier 53a of the second line 53 is formed on the common electrode layer 56, and this tunnel barrier 53a is
It is commonly connected to other tunnel barriers 52a and 54a at the step portion, ie, the S branch point.

On the other hand, in the ■branch, as shown in FIG. 11, the first □1- line 57, the second line 58, and the third line 59 are horizontally branched at the branch point.

Therefore, the lower electrode, tunnel barrier, and upper electrode of each of the first to third lines 57, 58, and 59 are formed on one plane.

Comparing the above-mentioned device structure shown in FIG. 9 with the above-mentioned S branch and T-branch, the first
, second and fourth three Josephson lines 1.2.4 S
A T-branch is constructed by three Josephson lines 1.2.3, first, second, and third. ■The upper electrode 21 of the second Josephson line 2 constituting the branch is connected to the upper electrode 11 of the first Josephson line 1 via the junction of the fourth Josephson line 4 and the superconductor 49. Ru.

Then, a bias current 1b of a required value is passed through the Josephson junction (hereinafter simply referred to as a junction) in each Josephson line 1.2.3.4, and the magnetic flux quantum is first transferred from the input end 3a side of the third Josephson line 3. When input, the magnetic flux quantum becomes a bias electric! It travels through the tunnel barrier 33 under the Lorentz force due to Ib, and is held at the branch of the T-branch formed by the first, second, and third Josephson lines 1.2.3. The circulating current due to this retained magnetic flux quantum acts as an auxiliary via current to the junction at the input end of the second Josephson line 2.

Next, in such a state, when a magnetic flux quantum is input to the input end 1a side of the first Josephson line 1, it propagates through the tunnel barrier 13, and at the branch part, its propagation path changes to the next one. controlled as follows.

That is, when a magnetic flux quantum is held in one branch of the T-branch as described above, the junction of the input end 2a of the second Josephson line 2 has a shunt valve for the bias current 1b as well as a Since the circulating current [S is added as an auxiliary bias mm, the second Josephson line 2 is in a state where it is easy for magnetic flux quanta to enter (input), and the magnetic flux quanta from the first Josephson line 1 is transmitted to the second Josephson track 24 side.

On the other hand, when no magnetic flux quantum is held in the branch, the magnetic flux quantum from the first Josephson line 1 is transferred to the fourth Josephson line forming the S branch with this first Josephson line 1 etc. It is transmitted to the track 4 side.

In this way, depending on whether or not magnetic flux quanta are retained at the branch part of the T-branch, the magnetic flux quantum from the first Josephson line 1 is transmitted to the second Josephson line 2 or to the fourth Josephson line. Ill see if it gets transmitted to Josephson Track 4.
be allied.

(Problems to be Solved by the Invention) In the conventional device, an S branch is configured by the first, second, and fourth 3iiJ Josephson lines 1.2.4, and among these, the fourth Josephson line 4 and the junction of the second Josephson line 2 are connected in series in two stages as shown in FIG. 10(B). For this reason, Josephson line 4 of i4
The bias current supplied to the second Josephson line 2
All of the current also flows through the junction of the two Josephson lines 2.4, making it difficult to independently supply bias current to both Josephson lines 2.4. Therefore, the power supply circuit for supplying bias current to each Josephson line 1, 2, 3, and 4 constituting the element becomes complicated. In addition, since the S branch is configured as a two-way junction in which each junction is stacked in two stages, when configuring a logic circuit in which elements are connected in multiple stages, it is necessary to use a multi-junction in which multiple junctions are stacked in multiple stages. Structure is needed.

However, such a multi-junction structure as shown in Fig. 10 (B
) There was a problem in that it was extremely difficult to realize the thin film type bonding shown in 7.

This invention was made based on the above circumstances. It is an object of the present invention to provide a magnetic flux m-element element that does not require an S-branch structure.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention has a structure in which a tunnel barrier is sandwiched between an upper electrode and a lower electrode made of a superconductor, and the magnetic flux is An element configured using at least three Josephson lines, first to third, each containing an input end and an output end of a quantum, the output end of the first Josephson line and the second Josephson line containing a quantum input end and an output end. Either the upper electrodes or the lower electrodes, only the upper electrodes, or only the lower electrodes are connected to the input end of the line by a resistor, and the input end of the third Josephson line is connected to the input end of the third Josephson line.
The propagation of the magnetic flux quantum from the Josephson line of The gist of the input end of the line is that upper electrodes and lower electrodes are connected with a superconductor to form a superconducting loop for holding the control magnetic flux quantum.

(Function) When the output end of the first Josephson line and the input end of the second Josephson line are connected through a resistor, the first
Whether or not the magnetic flux quantum transmitted through the Josephson line is input to the second Josephson line depends on the current value supplied to the junction at the input end of the second Josephson line.

Then, when the control magnetic flux quantum is transmitted from the input end of the third Josephson line, this control magnetic flux quantity hinge is transmitted between the output end of the third Josephson line and the second Josephson line. It is stopped and held in a superconducting loop formed between the input end and the input end. The magnetic flux quanta held in this superconducting loop causes a circulating current to flow at the junction of the input end of the second Josephson line, which acts as an auxiliary bias current i to When the current reaches a critical current value, the magnetic flux quantum that has been transmitted through the first Josephson line is input to the second Josephson line.

When the magnetic flux quantum for control is not held in the superconducting loop, the current at the input end of the second Josephson line does not reach the critical current value and the magnetic flux quantum that has been propagating through the first Josephson line is emitted to the outside from the resistor.

Therefore, the magnetic flux quantum for υ1iIl held in the superconducting loop controls the propagation of the magnetic flux quantum from the first Josephson line to the second Josephson line.

(Example) Embodiments of the present invention will be briefly described below with reference to the drawings.

The magnetic flux m-element according to this embodiment is constructed using at least three Josephson lines, first to third.

Here, there are two types of Josephson lines: distributed constant Josephson lines and lumped constant Josephson lines.
First, the distributed constant type Josephson line is constructed based on an 81-layer structure in which a tunnel barrier is sandwiched between an upper electrode and a lower electrode made of a superconductor. It is formed to have a length more than five times the penetration distance λj of London.

On the other hand, the lumped Josephson line has f
When ai14m structure is used as the first laminated structure part, this first
In addition to the laminated structure part, the second laminated structure part has an insulating layer having a thickness such that no tunnel current can flow between the upper electrode and the lower electrode made of a superconductor. The first laminated structure parts and the second laminated structure parts are alternately connected, and the length of the first laminated structure "fXa" is smaller than the London penetration distance λj.

Either the distributed parameter type Josephson line or the lumped parameter type Josephson line described above can be applied to the Josephson line in each of the following embodiments. In this section, the case where a distributed constant type Josephson line is applied is explained.

The first embodiment will be explained using FIGS. 1 to 3.

First, to explain the configuration of the magnetic flux quantum element, in Fig. 1,
10 is a first Josephson line, 20 is a second Josephson line, and 30 is a third Josephson line. Taking the first Josephson line 10 as an example, each Josephson line has a laminated structure in which a tunnel barrier 103 is sandwiched between an upper electrode 101 and a lower electrode 102 made of a superconductor. A bias current line 14 is connected to 101. Regarding the second Josephson line 20, in addition to the bias current line 15, an auxiliary bias current line 15 is provided near the input end 20a.
a is connected.

Also, each of the first, second, and third Josephson lines 10.20
．． 30 lower electrodes 102, 202, and 302 are commonly grounded to a ground plane (not shown) made of a superconductor.

The output end 10b of the first Josephson line 10 and the input end 20a of the second Josephson line 20 are connected by the resistor 5 at their upper electrodes 101 and 201. Here, a resistor means a non-superconductor made of a material having a resistance value.

Note that the resistor 5 has an upper electrode 101.20 as shown in the figure.
1, but also upper electrodes 101.201 and lower electrodes 102.202, or lower electrodes 102.
202 may be connected to each other.

Moreover, the input end 30a of the third Josephson line 30 is
It serves as an input terminal of a control magnetic flux quantum that controls the propagation of the magnetic flux suspender from the first Josephson line 10 to the second Josephson line 20, and the output terminal 30b of the third Josephson line 30 and the 2 Josephson line 20 input end 20
The upper electrodes 201 and 301 are connected to each other by a superconductor 7. The second Josephson line 20' and the third Josephson line 30 have their lower electrodes 202.30
The output end 30b of the third Josephson line 30 and the input end 20 of the second Josephson line 20 are connected to each other via a superconductor constituting a ground plane.
A superconducting loop is formed between the junction of the third Josephson line 30, the superconductor 7, the junction of the second Josephson line 20, and the path of the superconductor constituting the ground plane. ing. Hereinafter, this superconducting loop will be referred to as an inductance loop.

Next, the operation of the magnetic flux quantum element configured as described above will be explained.

Before explaining the operation of the device, first, the meaning of connecting the first and second Josephson lines 10 and 20 with the resistor 5 will be explained.

Magnetic flux cannot penetrate into the superconductor.

Therefore, in a Josephson line where the upper and lower electrodes are superconductors, the magnetic flux ω exists in the tunnel barrier, which has weak superconductivity and becomes normal conduction due to changes in current.

Therefore, magnetic flux quanta can enter and leave the Josephson line only at its ends. In order to extract magnetic flux quanta from the middle of such a Josephson line, it is necessary to make part of the upper or lower electrode a normal conductor, and this is achieved by connecting the Josephson line with a resistor. It is.

When the output end 10b of the first Josephson line 10 and the input end 20a of the second Josephson line 20 are connected through the resistor 5, the input end 10b of the second Josephson line 20 is connected at this connection point. The magnetic flux °ω that has propagated from the first Josephson line 10 depending on the current supplied to the junction at the end 20a enters the second Josephson line 20 (
input) or not. The condition for the magnetic flux m to be input to the second Josephson line 20 is such that the current supplied to the junction of the input end 2oa of the second Josephson line 20 is r j - IC + Ib'
... (1) This is the case when the critical current value 1j is reached. Here, IC is a circulating current associated with a magnetic flux quantum, and Ib' is a shunt valve for a bias current supplied to the junction of the input end 20a of the second Josephson line 20.

In other words, if a critical current Ij as shown in the above equation (0) is supplied to the junction of the input end 20a of the second Josephson line 20 to cause portex transition, a magnetic flux quantum will be transferred to the second Josephson line 20. can be invaded.

Next, the operation of the element will be explained. The flux quantum device of this example has two operating modes: a first operating mode and a second operating mode.

First, the first operation mode will be explained. 3rd at the beginning
When the magnetic flux m for control is transmitted from the input end 30a of the Josephson line 30, this magnetic flux quantum is transferred to the output end 30b of the third Josephson line 30 and the input end 2Qa of the second Josephson line 20. It is stopped and held by the inductance loop formed between the In the inductance loop, there is a circulating current I caused by this retained magnetic flux m.
C flows, and this circulating current 1c is supplied to the junction of the input end 20a of the second Josephson line 20 from the upper electrode 201 side toward the lower electrode 202 side.

Therefore, the circulating current 1c flows through the second Josephson line 2
serves as an auxiliary bias current for the junction of the input end 20a of the second Josephson line 20, and
The current supplied to the junction a reaches the critical current value Ij&: shown in equation (1) above, and the current flows to the second Josephson line 20.
The magnetic flux quantum becomes available for input.

In this state, the input end 10a of the first Josephson line 10
When a magnetic flux quantum is input to , this magnetic flux quantum propagates through the first Josephson line 10 and is further input to the second Josephson line 20 via the resistor 5 .

a, IJ If the magnetic flux quantum for III is not held in the inductance loop, the magnetic flux quantum that has propagated through the first Josephson line 10 is released from the resistor 5 to the outside.

The magnetic flux quantum input to the second Josephson line 20 is caused by the fact that both the upper electrodes 201 and 301 and the lower electrodes 202 and 302 of the second Josephson line 20 and the third Josephson line 30 exceed each other. Because they are connected by a conductor, they cannot escape to the outside of the junction, and from one input magnetic flux quantum, the second Josephson line 2
Magnetic flux quantum propagating 0 and third Josephson line 30
Magnetic flux quanta that propagate to the side are generated. The direction of the magnetic flux quantum propagating to the third Josephson line 30 is opposite to that of the control magnetic flux quantum held in the inductance loop.

The former propagates through the second Josephson line 20 to its output end 20b, and the latter causes annihilation with the control magnetic flux quantum held in the inductance loop, causing the magnetic flux m for III make the child disappear.

In this manner, the propagation of the magnetic flux quantum from the first Josephson line 10 to the second Josephson line 20 is controlled depending on whether or not the magnetic flux quantum for control is stopped in the inductance loop.

FIGS. 2 and 3 show the above-mentioned element operation confirmed by simulation. The simulation conditions are βG-3500 Ib/Ij=0.4. Here, βC is a well-known factor (anonymous number) called a pine camber parameter, Ib is a bias current, and Ij is a critical current value.

Figure 2 shows the simulation results when no magnetic flux quantum is input to the third Josephson line 30 before inputting the magnetic flux to the first Josephson line 10, and Figure 3 shows the simulation results for the third Josephson line 30. This is a simulation result when a magnetic flux matrix is input to 30. Both figures plot the temporal change in the phase of the junction in the Josephson line.

It can be determined that the magnetic flux quantum has passed through that point by a 2π change in phase. In FIG. 2, the magnetic flux base is propagated to the end of the first Josephson line 10 at the front stage, but there is no phase change in the second Josephson line 20 at the rear stage, and the flux is emitted from the resistor 5. It shows. On the other hand, FIG. 3 shows that the phase changes up to the end of the second Josephson line 20 in the latter stage, indicating that the magnetic flux quantum is propagating to the second Josephson line 20 through the resistor 5. There is. As mentioned above, the results shown in Figures 2 and 3 are
This shows that the propagation of other magnetic flux quanta is influenced by whether or not a magnetic flux quantum is input to the III input line.

Next, the second operation t-do will be explained.

In this mode of operation, an auxiliary bias current is supplied to the junction of the input end 20a of the second Josephson line 20 from the auxiliary bias current line 15a. With this auxiliary bias current supplied, first the first Josephson line 1
When a magnetic flux quantum is transmitted from the input end 10a of the second Josephson line 20, the magnetic flux is transmitted to the output end 20b of the second Josephson line 20, and the magnetic flux quantum is stopped and held in the inductance loop.

The circulating current accompanying the magnetic flux quantum stopped and held in the inductance loop from the first Josephson line 10 side flows through the junction of the input end 20a of the second Josephson line 20 from the lower electrode 202 to the upper electrode 201. and is canceled by the auxiliary bias current. When magnetic flux quanta propagate from the first Josephson line 10 in this state, the magnetic flux quanta are emitted from the resistor 5 to the outside because the state is the same as when no auxiliary bias current is supplied. This state is maintained until the magnetic flux quantum propagates from the third Josephson line 30 and is annihilated with the magnetic flux quantum previously held in the inductance loop. - Therefore, the third Josephson line 30 is
If magnetic flux quanta are transmitted periodically at every interval, no matter how many magnetic flux quanta are transmitted from the first Josephson line 10 in this fixed time interval, the output end of the second Josephson line 20 20b has the operational function that only the first magnetic flux is transmitted to the child.

Next, FIGS. 4 and 5 show a second embodiment of the present invention.

In this embodiment, a fourth Josephson line 40 is added and is juxtaposed to the third Josephson line 30. and the input end 20 of the second Josephson line 20
a and the upper electrodes 301.a of the output ends 30b, 40b of each of the third and fourth Josephson lines 30.40.
401 are independently connected by superconductors 7.8.

The input end 30a of the third Josephson line 30 and the fourth
The input ends 40a of the Josephson lines 40 are respectively input ends of the control magnetic flux quanta.

When a magnetic flux quantum is input from either the input end 30a or 40a of the third or fourth Josephson line 30.40, the magnetic flux quantum is transmitted to the respective Josephson line 3.
It is stopped and held in an inductance loop formed between the 0.40 output end 30b140b and the input end 20a of the second Josephson line 20.

In this state, if the magnetic flux quantum used as a timing signal by the bird is transmitted from the first Josephson line 10, if there is a holding magnetic flux quantum in any inductance loop, the magnetic flux quantum will be transmitted from the first Josephson line 10. The magnetic flux quantum passes through the resistor 5 to the second Josephson line 20 at the subsequent stage.
When there is no retained magnetic flux locus, the magnetic flux quantum from the first Josephson line 10 is emitted from the resistor 5. In other words, ORI functionality is realized.

In addition, the value of the resistor 5 is increased so that the magnetic flux m from the first Josephson line 10 cannot be input to the second Josephson line 20 with only the circulating current associated with holding one magnetic flux m. Then both the third and fourth Josephson lines 30
．． 40, the magnetic flux quantum is transmitted to the second Josephson line 20 in the subsequent stage.
NDII functionality can be realized.

FIG. 5 shows the dependence of the input of magnetic flux quanta into the second Josephson line 20 on the resistance and on the auxiliary bias current. The simulation conditions are βC=3500 Ib/Ij-0,4 Inductance of superconductor 8.7=40. pH.

The lower side of the characteristic line in FIG. 5 is the area where magnetic flux quanta are emitted from the resistor 5 and does not propagate, and the upper side is the area where magnetic flux quanta are transmitted from the first Josephson line 10 to the second Josephson line 20. It is an area.

As is clear from the characteristics shown in Figure 5, the auxiliary bias current, in other words, the circulating current of the retained magnetic flux m, is 0.3 mA.
Then, until the resistance value of the resistor 5 reaches 0°80, the magnetic flux quantum is transmitted from the first Josephson line 10 to the second Josephson line 20 with a circulating current accompanying one magnetic flux quantum. If it exceeds this, it performs an OR operation, and if it exceeds that, it performs an AND operation, in which the circulating currents associated with one magnetic flux quantum are superimposed and only propagate.

FIG. 6 shows a third embodiment of the invention.

This embodiment further adds a fifth Josephson line 50 through which magnetic flux quanta are transmitted from the first Josephson line 10 to the configuration shown in FIG. 4 which is the second embodiment. It is installed in parallel with the Josephson line 20 of No. 2.

The output end 10b of the first Josephson line 10 and the input end 50a of the fifth Josephson line 50 are connected to the upper electrode 10.
1.501 are connected to each other by a resistor 6, and the output end 40b of the fourth Josephson line 40 and the input end 50a of the fifth Josephson line 50 are connected to the upper electrode 401.501.
They are connected to each other by a superconductor 8.

Note that the resistor 5 has an upper electrode 101.501 as shown in the figure.
Not only between the upper electrodes 101.501 but also between the lower electrodes 102.502 as in the case of the first embodiment.
The lower electrodes 102 and 502 may be connected to each other or only to the lower electrodes 102 and 502.

As mentioned above, the magnetic flux m-element of this embodiment has the first and second
, the three fifth Josephson lines 10, 20, and 50 form a resistance-coupled branch, and the input terminals 20a and 150a of the second and fifth Josephson lines 20, 50 on the subsequent stage are each connected to a superconductor. It has a structure in which third and fourth Josephson lines 30.40 for control magnetic flux quantum input are connected via a body 7.8.

To explain the operation, magnetic flux quanta are transmitted from both the third and fourth Josephson lines 30, 40, and the connection between the fourth Josephson line 40 and the fifth Josephson line 50 and the third Josephson line Magnetic flux quanta are stopped in the inductance loop formed at the connection between the line 30 and the second Josephson line 20. After the magnetic flux quantum as a control input is input, the magnetic flux quantum is transmitted to the first Josephson line 10 as a trigger. The magnetic flux quantum that propagates from the first Josephson line 10 does not propagate to the Josephson line where the magnetic flux m is held in the inductance loop at its input end, but does not propagate to the Josephson line where the magnetic flux is not held. It is emitted to the outside from the resistor 5.6.

Therefore, depending on the presence or absence of a magnetic flux quantum as a control input, "it does not propagate to either the second Josephson line 20 or the fifth Josephson line 50", "it propagates only to one side", or "it propagates to both". It is possible to control the transmission in three modes: ``broadcast''.Moreover, the magnetic flux m is transmitted to the output at the timing of the magnetic flux quantum transmitted from the first Josephson line 10, which is the trigger signal. The timing of the magnetic flux quanta propagating from the input end 30a and the input end 40a is controlled by the second Josephson line 20 and the fifth
A function as a timing adjustment circuit capable of time adjustment is realized at the input ends 20a, 50a of the Josephson line 50.

FIG. 7 shows a fourth embodiment of the invention.

In this embodiment, in the device having the structure shown in FIG. 6, which is the third embodiment, the output end 20 of the second Josephson line 20 is
b and the input end 40a of the fourth Josephson line 40 connect the upper electrodes 201 and 401 with the superconductor 17, and the output end 50b of the fifth Josephson line 50 and the input end 40a of the third Josephson line 30. The input end 30a is the upper voltage l4i50
1.301 are connected to each other by a superconductor 18.

To explain the operation, magnetic flux quanta are transmitted from the fourth Josephson line 40 and held in the inductance loop formed between the fourth Josephson line 40 and the fifth Josephson line 50. Initialize first. After that, when the magnetic flux quantum is transmitted from the first Josephson line 10, the magnetic flux quantum is transmitted to the fifth Josephson line 50 where the magnetic flux quantum is held in the inductance loop at the resistance branch, and the retained magnetic flux quantum The operation is such that the signal does not propagate to the second Josephson line 20 where there is no line.

The magnetic flux quantum transmitted to the fifth Josephson line 50 is transferred to the fourth Josephson line 40 and the fifth Josephson line 5.
The magnetic flux annihilates with the retained magnetic flux quantum in the inductance loop configured between It is stopped and held in an inductance loop formed between the second Josephson line 20.

Next, when the magnetic flux quantum propagates from the first Josephson line 10 again, this time it propagates only to the second Josephson line 20 where there is a retained magnetic flux quantum, and then to the third Josephson line 30 and the second Josephson line 10. The inductance loop formed between the Josephson line 20 annihilates the retained magnetic flux quantum, and also propagates from the second Josephson line 20 to the fourth Josephson line 40. The inductance loop formed between the Josephson line 50 of

As described above, in this embodiment, the magnetic flux quanta propagated from the first Josephson line 10 can be distributed alternately to the output end 20b and the output end 50b. Therefore, if this embodiment is used, a 1/2 frequency divider can be configured by inserting a magnetic flux quantum into the input terminal 10a and outputting the output terminal 2ob or the output terminal 50b, and by connecting these in series. A counter function can be realized.

FIG. 8 shows a fifth embodiment of the invention.

This embodiment includes three Josephson lines 10.20.30, first, second, and third, and three Josephson lines 40.50.60, fourth, fifth, and sixth. The device structure of the first embodiment shown in FIG.
1 are connected to each other by a superconductor 17, and the output end 50b of the fifth Josephson line 50 and the input end 30a of the third Josephson line 30 are connected to the upper electrodes 501 and 301 by a superconductor 17. This is what I did.

To explain the operation, a magnetic flux quantum is transmitted from the input end 30a of the third Josephson line 30, and the magnetic flux is transferred to the inductance loop formed between the third Josephson line 30 and the second Josephson line 20. First, initialization is performed to hold m children.

When magnetic flux quanta are transmitted from the Josephson line 10 of the rear cylinder 1, the input end 20a of the second Josephson line 20 is
Since a circulating current associated with the retained magnetic flux quantum is supplied to the magnetic flux element, the magnetic flux element is transmitted to the second Josephson line 20. This magnetic flux quantum annihilates with the retained magnetic flux quantum of the inductance loop between the second Josephson line 20 and the third Josephson line 30, and is transmitted from the second Josephson line 20 to the sixth Josephson line. Banshi No. 6
Josephson line 60 and the fifth Josephson line 50
It is stopped and held in the inductance loop between.

Next, when the magnetic flux quantum propagates from the first Josephson line 10 again, this time there is no retained magnetic flux quantum in the inductance loop part due to pair annihilation, so the circulating current flows to the input end 20a of the second Josephson line 20. Magnetic flux quanta are emitted from the resistor to the outside without being supplied.

However, in this state, the fourth Josephson line 40
When the magnetic flux quantum propagates from the sixth Josephson line 6
Since the magnetic flux is held in the inductance loop between 0 and the fifth Josephson line 50, the magnetic flux quantum is the fifth
Josephson Line 50. The magnetic flux quantum propagated to the fifth Josephson line 50 is annihilated in the inductance loop between the fifth Josephson line 50 and the sixth Josephson line 60, and the magnetic flux quantum is transferred from the fifth Josephson line 50 to the third Josephson line 50. It propagates to the Josephson line 3O and is stopped and held in the inductance loop between the third Josephson line 30 and the second Josephson line 20.

As mentioned above, this embodiment enables flip-flop-like operation in which the next operation is controlled by the previous operation, and by connecting the elements of this embodiment in series, a combinational circuit of logic circuits can be realized. realizable.

As described above, each of the embodiments can be easily constructed without using an S branch, in other words, without using multiple junctions, and compared to the conventional technology, other magnetic flux quanta are generated by internal magnetic flux quanta rather than by externally applied current. It has the characteristic that propagation control is possible.

[Effects of the Invention] As explained above, according to the present invention, the output end of the third Josephson line to which the control magnetic flux quantum is input and the second
What is the input end of the Josephson line of Since it is connected to the input end of the Josephson line of the cylinder 2 through the resistor, it is a simple configuration that does not require an S branch, or in other words, a multi-junction structure, and the Josephson line of the next stage is The magnetic flux to has the advantage that it is possible to realize a magnetic flux quantum that controls the propagation of the child.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a first embodiment of the magnetic flux quantum according to the present invention, and FIGS. 2 and 3 are characteristic diagrams showing the propagation characteristics of the magnetic flux quantum in the Josephson line in the first embodiment. FIG. 2 is a characteristic diagram when no control magnetic flux quantum is input, FIG. 3 is a characteristic diagram when a control magnetic flux quantum is input, and FIG. 4 is a configuration showing a second embodiment of the present invention. figure,
FIG. 5 is a characteristic diagram showing the dependence of the input of magnetic flux quanta to the second Josephson line on resistance and auxiliary bias current in the second embodiment of the same as above, and FIG. 6 is a configuration showing the third embodiment of the present invention. 7 is a block diagram showing a fourth embodiment of the invention, FIG. 8 is a block diagram showing a fifth embodiment of the invention, and FIG. 9 is a block diagram showing a fifth embodiment of the invention.
The figure is a configuration diagram showing a conventional single magnetic flux insertion gate, Fig. 10 is a perspective view showing a conventional S branch structure, and Fig. 11 is a conventional T
It is a perspective view showing a branch structure. 5.6: Resistor, 7.8.17.18: Superconductor 10.20.30.40.50.60: Josephson line, 10a, 20a, 30a, 40a150a, 60a: Input end, 10b, 20b130b , 40b, 50b, 60b=output end, 101.201.301.401.501.601: Upper electrode, 102.202.302.402.502.602: Lower electrode, 103.203.303.403.503. 603: Tunnel barrier.

Claims (5)

[Claims] (1) A Josephson line having a configuration in which a tunnel barrier is sandwiched between an upper electrode and a lower electrode made of a superconductor, and an input end and an output end for magnetic flux quanta, is provided at least in three stages, from first to third. An element configured by using a plurality of electrodes, wherein the upper electrodes are connected between the output end of the first Josephson line and the input end of the second Josephson line, between the upper electrodes and between the lower electrodes, only between the upper electrodes, or between the lower electrodes. A control magnetic flux quantum that controls the propagation of the magnetic flux quantum from the first Josephson line to the second Josephson line by connecting one of them with a resistor and connecting the input end of the third Josephson line to the second Josephson line. The output end of the third Josephson line and the input end of the second Josephson line are connected by a superconductor between the upper electrodes and between the lower electrodes to hold the control magnetic flux quantum. A magnetic flux quantum device characterized by forming a superconducting loop for the purpose of (2) A fourth Josephson line is installed in parallel with the third Josephson line, and the output end of the fourth Josephson line and the input end of the second Josephson line are connected to the upper electrode and the lower electrode. A patent claim characterized in that the electrodes are connected to each other by a superconductor, and the input end of the fourth Josephson line is used as the input end of another control magnetic flux quantum, and two input ends of the control magnetic flux quantum are provided. The magnetic flux quantum device according to the range 1 above. (3) A fourth Josephson line having an input end for another control magnetic flux quantum is arranged in parallel with the third Josephson line, and the magnetic flux quantum is transmitted from the first Josephson line. A fifth Josephson line is arranged in parallel with the second Josephson line, and the upper electrode and the lower electrode are connected between the output end of the first Josephson line and the input end of the fifth Josephson line. Either the electrodes, only the upper electrodes, or only the lower electrodes are connected with a resistor, and the output end of the fourth Josephson line and the input end of the fifth Josephson line are connected between the upper electrodes and between the upper electrodes and the input end of the fifth Josephson line. The lower electrodes are connected to each other with a superconductor to provide two input terminals for controlling magnetic flux quanta, and each of the two controlling magnetic flux quanta controls the propagation of the magnetic flux quantum from the first Josephson line. The magnetic flux quantum device according to claim 1, characterized in that two Josephson lines are provided. (4) The output end of the second Josephson line and the input end of the fourth Josephson line are connected by connecting their upper electrodes with a superconductor, and the output end of the fifth Josephson line and the input end of the third Josephson line are connected to each other by a superconductor. 4. The magnetic flux quantum device according to claim 3, wherein upper electrodes of the input end of the son line are connected to each other by a superconductor. (5) Fourth to sixth Josephson lines corresponding to the first to third Josephson lines are attached, and the output end of the fourth Josephson line and the input of the fifth Josephson line Either the upper electrodes or the lower electrodes, only the upper electrodes, or only the lower electrodes are connected with a resistor, and the input end of the sixth Josephson line is connected to the fourth Josephson line. An input terminal for another control magnetic flux quantum that controls the propagation of the magnetic flux quantum from the line to the fifth Josephson line, and an output end of the sixth Josephson line and an input end of the fifth Josephson line. The upper electrodes and the lower electrodes are connected with a superconductor, and the output end of the second Josephson line and the input end of the sixth Josephson element are connected with the upper electrodes with a superconductor. , the output end of the fifth Josephson line and the input end of the third Josephson line have their upper electrodes connected to each other by a superconductor. .