KR102272930B1 - Electride with wigner crystal and menufacturing method of wigner crystal - Google Patents

Abstract

The present invention relates to an electronic material having a Wigner crystal formed on its surface. Unlike conventional Wigner crystals that are formed only under extreme conditions, the electronic material on which the Wigner crystal of the present invention is formed can form the Wigner crystal on the solid surface rather than the liquid surface at a relatively high temperature without an external magnetic field. It can be used for quantum computing calculation devices using the excellent electrical and magnetic properties of crystals, single-electron transistors, switching electronic devices, spin-controlled magnetic devices, and optical devices using plasmons.

Description

ELECTRIDE WITH WIGNER CRYSTAL AND MENUFACTURING METHOD OF WIGNER CRYSTAL

The present invention relates to an electronic material having a Wigner crystal formed thereon and a method for forming a Wigner crystal, and more particularly, to an electron material having a layered structure, characterized in that the Wigner crystal is formed on the surface, and a Wig on the surface of the electron material It's about how you form crystals.

Electrons are new substances that directly determine the functionality of materials regardless of constituent elements and structural factors, while electrons exist in the form of interstitial electrons in the empty space inside the crystal rather than around the nucleus of an atom. to be. Electron materials are materials that can be used in various fields such as electron emission materials, catalyst materials, and magnetic materials due to their low work function, high electron transfer efficiency, and high magnetic entropy change.

A Wigner crystal means electrons in a crystallized state, that is, in a solid state, by periodically arranging electrons. The Wigner crystal was first observed by electrons trapped on liquid helium (He), and then also at the GaAlAs/GaAs interface, a semiconductor heterojunction.

However, they are only temporarily implemented under extreme conditions (a strong magnetic field of 20 Tesla or more at less than 1 K for liquid helium and less than 0.1 K for heterojunctions), so it is almost impossible to control the properties of the resulting Wigner crystals. Due to the above problems, it is very difficult to apply the Wigner crystal to practical electronic and magnetic devices such as quantum computing or single electron transistors.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and it is an object of the present invention to provide an electronic material in a solid state having a Wigner crystal formed on the surface.

Another object of the present invention is to provide a method for forming a Wigner crystal on the surface of a solid electron oxide at a relatively high temperature of 1 K to 100 K rather than a cryogenic temperature of less than 1 K.

According to one aspect of the present invention, there is provided an electronized material represented by any one of the following Chemical Formulas 1 to 3 and an electronized material for forming a Wigner crystal including a Wigner crystal on the surface.

<Formula 1>

X ₂ C

In Formula 1,

X is Gd, Sc, Y, Dy, Ho, Ce, Er or Tb,

<Formula 2>

Y ₂ N

In Formula 2,

Y is Ca, Sr or Ba;

<Formula 3>

Z Cl

In Formula 3,

Z is Y, La, Zr or Hf.

The electronic material may be a single crystal, a polycrystal, or a thin film.

The electronic material has a layered structure and may include interstitial electrons arranged in two dimensions between layers.

The Wigner electron density of the crystal is 10 ⁸ cm ^-2 to 10 ¹³ cm ^- can be ^two days.

The Wigner crystals may exist in an inert gas atmosphere at a low temperature or a high vacuum atmosphere.

The low temperature may be 1 K to 100 K.

The inert gas may include at least one selected from helium, argon, neon, krypton, xenon, and nitrogen.

The high vacuum state may be a vacuum degree ^{of 10 -11} Torr to 10 ^{-5 Torr.}

According to another aspect of the present invention, (a) preparing an electron material represented by any one of the following Chemical Formulas 1 to 3; (b) cleaving the surface of the electron material in a low-temperature inert gas atmosphere or ultra-vacuum state; and (c) dosing an alkali atom to the surface of the cleaved electron oxide;

<Formula 1>

X ₂ C

In Formula 1,

X is Gd, Sc, Y, Dy, Ho, Ce, Er or Tb,

<Formula 2>

Y ₂ N

In Formula 2,

Y is Ca, Sr or Ba;

<Formula 3>

Z Cl

In Formula 3,

Z is Y, La, Zr or Hf.

The alkali atom may be at least one selected from lithium, sodium, potassium, rubidium, and cesium.

The low temperature may be 1 K to 100 K.

The inert gas may include at least one selected from helium, argon, neon, krypton, xenon, and nitrogen.

The high vacuum state may be a vacuum degree ^{of 10 -11} Torr to 10 ^{-5 Torr.}

According to another aspect of the present invention, there is provided an electronic device including the Wigner crystal-forming electronic material.

According to another aspect of the present invention, there is provided a magnetic device including the electron oxide forming the Wigner crystal.

According to another aspect of the present invention, there is provided an optical device including the Wigner crystal-forming electronic material.

Unlike conventional Wigner crystals that require an extreme environment, the electronic material in which Wigner crystals are formed on the surface of the present invention can form Wigner crystals on a solid surface at a relatively high temperature without an external magnetic field. , quantum computing using magnetic properties, single-electron transistors, switching electronic devices, spin-controlled magnetic devices, and optical devices using plasmons.

In addition, the method of forming a Wigner crystal of the present invention can form a Wigner crystal on the surface of a solid electron material at a relatively high temperature of 1 K to 100 K rather than a cryogenic temperature of less than 1 K.

1 shows a method of forming a Wigner crystal of the present invention.
2 is a result of measuring the electronic structure of the Wigner crystal prepared according to Example 1 by angle-resolved photoemission spectroscopy.
3 is a simulation result of the formation of a Wigner crystal on the surface of an electron material based on the measurement result of each resolution photoelectron spectroscopy.

Advantages and features of the present invention, and methods for achieving them, will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings.

However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms.

The examples in this specification are provided so that the disclosure of the present invention is complete, and to fully inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention, and the present invention is defined by the scope of the claims will only be

Accordingly, in some embodiments, detailed descriptions of well-known components, well-known operations, and well-known techniques may be omitted to avoid obscuring the present invention.

In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase, and elements and operations referred to as 'comprising (or having)' do not exclude the presence or addition of one or more other elements and operations. .

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs.

Hereinafter, the electronic material in which the Wigner crystal of the present invention is formed will be described in detail.

The electron material in which the Wigner crystal is formed includes an electron material represented by any one of the following Chemical Formulas 1 to 3 and a Wigner crystal on the surface.

<Formula 1>

X ₂ C

In Formula 1,

X is Gd, Sc, Y, Dy, Ho, Ce, Er or Tb,

<Formula 2>

Y ₂ N

In Formula 2,

Y is Ca, Sr or Ba;

<Formula 3>

Z Cl

In Formula 3,

Z is Y, La, Zr or Hf.

The electronic material may be a single crystal, a polycrystal, or a thin film.

The electronic material may have a layered structure.

The Wigner crystal refers to a lattice composed of only electrons, that is, a crystal of electrons, and is generally a crystal composed of electrons that are not bound to an atomic orbital of an element constituting a material.

The electron concentration of the Wigner crystal may be 10 ⁸ cm ^-2 to 10 ¹³ cm ^-2 .

The electron material is a two-dimensional electron material in which interstitial electrons are distributed in a two-dimensional space, and the electron material is cleaved in a low-temperature and high-vacuum atmosphere to form a two-dimensional electron gas on the surface of the electron material.

The two-dimensional electron gas is a two-dimensional electron gas that is not bound to an atomic orbital of an element constituting the material, unlike that generated at the interface between the superlattice and the heterogeneous oxide thin film.

By introducing (dosing) an alkali atom into the two-dimensional electron gas, the Wigner crystal may be formed by a method of reducing the electron density of the two-dimensional electron gas.

The two-dimensional electron gas is collectively referred to as a two-dimensional electron gas (electron gas) and a two-dimensional electron liquid (electron liquid) electronic state.

The chemical composition ratio of the electron compound represented by any one of Formulas 1 to 3 may have a value within the range of ±5 mol.% of each element based on the stoichiometric composition ratio according to the manufacturing method.

The Wigner crystal may preferably exist in an inert gas atmosphere at a low temperature, and the inert gas may be helium, argon, neon, krypton, xenon, nitrogen, or the like.

The low temperature may be 1 K to 100 K. If it exceeds 100 K, the two-dimensional electron gas collapses and Wigner crystals cannot be formed.

The Wigner crystal may exist in a high vacuum state in addition to a low-temperature inert gas atmosphere, and the high vacuum may be a vacuum degree ^{of 10 -11} Torr to 10 ^{-5 Torr.}

Hereinafter, a method for forming a Wigner crystal of the present invention will be described.

First, an electronic material represented by any one of the following Chemical Formulas 1 to 3 is prepared (step a).

<Formula 1>

X ₂ C

In Formula 1,

X is Gd, Sc, Y, Dy, Ho, Ce, Er or Tb,

<Formula 2>

Y ₂ N

In Formula 2,

Y is Ca, Sr or Ba;

<Formula 3>

Z Cl

In Formula 3,

Z is Y, La, Zr or Hf.

Next, the surface of the electron material is cleaved in a low-temperature inert gas atmosphere or in a high vacuum state (step b).

The cleaving is a method of exfoliating the surface of the electronic material by fixing a solid rod on the electronic material and applying a physical impact to the fixed rod.

A two-dimensional electron gas may be formed on the surface of the electron material by the cleaving.

The inert gas may be helium, argon, neon, krypton, xenon, nitrogen, or the like.

The low temperature may be 1 K to 100 K. If it exceeds 100 K, the two-dimensional electron gas may collapse.

The high vacuum may be a vacuum degree ^{of 10 -11} Torr to 10 ^{-5 Torr.}

Finally, an alkali atom is introduced into the surface of the cleaved electron oxide (step c).

More specifically, by introducing an alkali atom into the two-dimensional electron gas formed by the cleaving, the electron density of the two-dimensional electron gas is lowered to form a Wigner crystal.

The alkali atom is lithium (Li), sodium (Na), potassium (K), rubidium (Rb) or cesium (Cs).

The electronic material in which the Wigner crystal is formed may be applied to electronic devices such as single-electron transistors, devices for quantum computing calculations, and switching devices. In addition, the electronic material in which the Wigner crystal is formed may be applied to a magnetic device such as a spin control device, or may be applied to an optical device.

[Example]

Example 1

Gd and C are mixed at a molar ratio of 2: 1 by melting and synthesizing a raw material at a high temperature, followed by cooling _{to prepare a Gd 2} C electron. The synthesis atmosphere is conducted in an inert gas or a vacuum atmosphere having a pressure of ^{10 -1 Torr or less.} The synthesis method uses an electric furnace or arc melting method for a high temperature of 1,000 ℃ or more. The synthetic Gd ₂ C by using a floating zone (floating zone) or Czochralski (Czochralski) method was grown as a single crystal Gd ₂ C.

Prepare a sample by processing single-crystal Gd ₂ C in a glove box in an argon gas atmosphere to the size of a sample holder that meets the standard of each resolution photoelectron emission spectroscopy equipment model to be used for measurement.

The prepared sample is loaded into the chamber of a photoelectron emission spectroscopy equipment for each resolution, and the temperature is lowered to 100 K or less at a pressure of ^{10 -9 Torr or less, and then the temperature is stabilized.} Thereafter, the surface of the sample is fractured using the above-mentioned cleaving method in a stabilized atmosphere of 100 K or less to form a two-dimensional electron gas on the surface of the sample.

Angular resolution photoelectron spectroscopy was performed while dosing potassium (K) atoms on the surface of the sample, and the results are shown in FIG. 2 .

Example 2

A raw material prepared by quantitatively mixing Ca and Ca ₃ N ₂ in a molar ratio of 1:1 is reacted at a high temperature and then cooled _{to prepare Ca 2} N electronized material. The synthesis atmosphere is ^{conducted under an inert gas or a pressure of 10 -3} Torr or less. The synthesis method uses an electric furnace for high temperature over 800 °C.

After lowering the temperature of Ca ₂ N from ^{a pressure of 10 -9} Torr or less to 100 K or less, the temperature is stabilized. After breaking the surface of Ca ₂ N by using the above-mentioned cleaving method in a stabilized atmosphere under 100 K to form a two-dimensional electron gas in the Ca ₂ N surface.

Finally, potassium atoms _{are dosed on the Ca 2} N surface to form Wigner crystals.

Example 3

A raw material prepared by quantitatively mixing La and LaCl ₃ in a molar ratio of 2 : 1 is reacted in a solid phase at a high temperature, and then cooled to prepare a LaCl electron. The synthesis atmosphere is conducted in an inert gas or a vacuum atmosphere having a pressure of ^{10 -3 Torr or less.} The synthesis method uses an electric furnace for high temperature over 500 °C.

After lowering the temperature of LaCl to 100 K or less in a vacuum atmosphere having a pressure ^{of 10 -9 Torr or less, the temperature is stabilized.} Thereafter, the surface of LaCl is fractured using the above-mentioned cleaving method in a stabilized atmosphere of 100 K or less to form a two-dimensional electron gas on the surface of LaCl.

Finally, potassium atoms are dosed onto the LaCl surface to form Wigner crystals.

Test Example 1: Confirmation of electronic structure through angular resolution photoelectron emission spectroscopy

_{According to Example 1, Gd 2} C having a two-dimensional electron gas formed on the surface was measured by angle-resolved photoelectron emission spectroscopy and is shown in FIG. 2 . It was confirmed that a parabolic energy band existed near the gamma (Γ) point (indicated by a red square). The corresponding energy band represents the two-dimensional electron gas formed on the surface of the cleaved electron material. After that, it was confirmed that the above-mentioned energy band gradually disappeared by dosing potassium on the surface. This indicates that the electron density of the two-dimensional electron gas decreases.

Test Example 2: Identification of the formation process of Wigner crystals through surface electronic structure simulation

When the electron density of the two-dimensional electron gas decreases below a critical value, a Wigner crystal is formed. In Test Example 1, it was confirmed that the electron density of the two-dimensional electron gas was decreased and the corresponding energy band disappeared. Based on these results, surface electronic structure simulation was performed to verify whether Wigner crystals were formed due to the decrease in electron density.

FIG. 3 is a result of simulating the surface electronic structure based on the results of angular resolved photoelectron emission spectroscopy of FIG. 2 . The surface electronic structures simulated using the measurement results indicated by a, b, and c in FIG. 2 correspond to a, b, and c of FIG. 3 . In addition, the theoretical calculation result assuming that the Wigner crystal is formed on the surface is the right figure (represented by simulation) of FIG. 3 . It can be seen that the two-dimensional electron gas having an amorphous structure (FIG. 3a) is crystallized in the form of a Wigner crystal (FIG. 3c) due to the decrease in electron density by alkali ion dosing.

Claims (16)

Including an electron material represented by any one of the following Chemical Formulas 1 to 3 and a Wigner crystal on the surface,
The electron concentration of the Wigner crystal will be 10 ⁸ cm ^-2 to 10 ¹³ cm ^-2 ,
Wigner crystal forming electron cargo.
<Formula 1>
X ₂ C
In Formula 1,
X is Gd, Sc, Y, Dy, Ho, Ce, Er or Tb,
<Formula 2>
Y ₂ N
In Formula 2,
Y is Ca, Sr or Ba;
<Formula 3>
Z Cl
In Formula 3,
Z is Y, La, Zr or Hf.
The method of claim 1,
The electron material is a Wigner crystal forming electron material, characterized in that the single crystal, polycrystalline or thin film.
The method of claim 1,
The electron material has a layered structure, and the electron material for forming a Wigner crystal, characterized in that it includes interstitial electrons arranged in two dimensions between the layers.
delete The method of claim 1,
The Wigner crystal forming electron material, characterized in that the Wigner crystal exists in an inert gas atmosphere at a low temperature or a high vacuum atmosphere.
6. The method of claim 5,
The low temperature is 1 K to 100 K, characterized in that the crystal forming electrons of Wigner.
6. The method of claim 5,
The inert gas is a Wigner crystal forming electron material, characterized in that it comprises at least one selected from helium, argon, neon, krypton, xenon, and nitrogen.
6. The method of claim 5,
The high vacuum state is a Wigner crystal forming electron material, characterized in that the vacuum degree of ^{10 -11} Torr to 10 ^{-5 Torr.}
(a) preparing an electron product represented by any one of the following Chemical Formulas 1 to 3;
(b) cleaving the surface of the electron material in a low-temperature inert gas atmosphere or ultra-vacuum state; and
(c) dosing an alkali atom to the surface of the cleaved electron oxide;
A method of forming a Wigner crystal comprising
<Formula 1>
X ₂ C
In Formula 1,
X is Gd, Sc, Y, Dy, Ho, Ce, Er or Tb,
<Formula 2>
Y ₂ N
In Formula 2,
Y is Ca, Sr or Ba;
<Formula 3>
Z Cl
In Formula 3,
Z is Y, La, Zr or Hf.
10. The method of claim 9,
The alkali atom is a method of forming a Wigner crystal, characterized in that at least one selected from lithium, sodium, potassium, rubidium and cesium.
10. The method of claim 9,
The low temperature is a method of forming a Wigner crystal, characterized in that 1 K to 100 K.
10. The method of claim 9,
The inert gas is a method of forming a Wigner crystal, characterized in that it comprises at least one selected from helium, argon, neon, krypton, xenon, and nitrogen.
10. The method of claim 9,
The high vacuum state is a method of forming a Wigner crystal, characterized in that the vacuum degree of ^{10 -11} Torr to 10 ^{-5 Torr.}
An electronic device comprising the electronic material for forming the Wigner crystal of claim 1 .
A magnetic device comprising the electron oxide forming the Wigner crystal of claim 1 .
An optical device comprising the electronic material for forming the Wigner crystal of claim 1 .

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