Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi

Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi

Performed full-relativistic DFT calculations have demonstrated that thin HgTe layers are metallic and, with increasing thickness, do not become insulators – either ordinary band insulators or topological insulators. The variations of the potential at the CdTe–HgTe interfaces are found to be negligib...

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Date:2021
Main Author: Yakovkin, I.N.
Format: Article
Language:English
Published: Publishing house "Academperiodika" 2021
Subjects:
поверхневi стани
DFT-розрахунки
HgTe–CdTe шари
Online Access:https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2020235
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Journal Title:Ukrainian Journal of Physics

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Ukrainian Journal of Physics
id ujp2-article-2020235
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spelling ujp2-article-20202352021-08-04T13:26:29Z Surface and Interface Bands of the CdTe–HgTe–CdTe Heterostructure: Evidence of Metallicity Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi Yakovkin, I.N. surface states density functional calculations HgTe–CdTe layers surface states поверхневi стани DFT-розрахунки HgTe–CdTe шари Performed full-relativistic DFT calculations have demonstrated that thin HgTe layers are metallic and, with increasing thickness, do not become insulators – either ordinary band insulators or topological insulators. The variations of the potential at the CdTe–HgTe interfaces are found to be negligible in comparison with those at the terminating surfaces of the CdTe–HgTe–CdTe films, so that the interfaces in fact do not form any potential well. It is shown that the interface-related bands of the CdTe–HgTe–CdTe films are situated well below EF, so that a dominant input into the density of states at EF and, therefore, to the conductivity is provided not by the interface states, but by the surface bands of the net layered system. It is reasonable therefore to consider an alternative interpretation of the reported thickness dependence of the conductivity of the system, such as the possible surface segregation of components or unavoidable contaminations, which seems much more realistic than the interpretation based on involving topological insulators and topologically protected surface states. Проведенi повнорелятивiстськi DFT розрахунки продемонстрували, що тонкi шари HgTe є металевими i зi збiльшенням товщини не можуть стати iзоляторами – анi звичайними, анi топологiчними. Варiацiї потенцiалу на iнтерфейсах CdTe–HgTe виявляються незначними порiвняно з тими, що на зовнiшнiх поверхнях плiвок CdTe–HgTe–CdTe, так що iнтерфейси насправдi не утворюють потенцiального колодязя. Показано, що iнтерфейснi зони плiвок CdTe–HgTe–CdTe розташованi набагато нижче EF, так що домiнуючий внесок у густину станiв на EF, а отже i на провiднiсть, забезпечується не станами iнтерфейсу, а поверхневими зонами всiєї шаруватої системи. Тому пропонується розглянути альтернативну iнтерпретацiю повiдомленої залежностi провiдностi системи вiд товщини, наприклад, можливу поверхневу сегрегацiю компонентiв або неминучi забруднення, що здається набагато бiльш реалiстичним, нiж iнтерпретацiя, заснована на концепцiї топологiчних iзоляторiв. Publishing house "Academperiodika" 2021-08-04 Article Article Original Research Article (peer-reviewed) Оригінальна дослідницька стаття (з незалежним рецензуванням) application/pdf https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2020235 10.15407/ujpe66.7.630 Ukrainian Journal of Physics; Vol. 66 No. 7 (2021); 630 Український фізичний журнал; Том 66 № 7 (2021); 630 2071-0194 2071-0186 10.15407/ujpe66.7 en https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2020235/1865 Copyright (c) 2021 Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine
institution Ukrainian Journal of Physics
baseUrl_str
datestamp_date 2021-08-04T13:26:29Z
collection OJS
language English
topic поверхневi стани
DFT-розрахунки
HgTe–CdTe шари
spellingShingle поверхневi стани
DFT-розрахунки
HgTe–CdTe шари
Yakovkin, I.N.
Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi
topic_facet surface states
density functional calculations
HgTe–CdTe layers
surface states
поверхневi стани
DFT-розрахунки
HgTe–CdTe шари
format Article
author Yakovkin, I.N.
author_facet Yakovkin, I.N.
author_sort Yakovkin, I.N.
title Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi
title_short Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi
title_full Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi
title_fullStr Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi
title_full_unstemmed Поверхневi та iнтерфейснi зони гетероструктури CdTe–HgTe–CdTe: докази металевостi
title_sort поверхневi та iнтерфейснi зони гетероструктури cdte–hgte–cdte: докази металевостi
title_alt Surface and Interface Bands of the CdTe–HgTe–CdTe Heterostructure: Evidence of Metallicity
description Performed full-relativistic DFT calculations have demonstrated that thin HgTe layers are metallic and, with increasing thickness, do not become insulators – either ordinary band insulators or topological insulators. The variations of the potential at the CdTe–HgTe interfaces are found to be negligible in comparison with those at the terminating surfaces of the CdTe–HgTe–CdTe films, so that the interfaces in fact do not form any potential well. It is shown that the interface-related bands of the CdTe–HgTe–CdTe films are situated well below EF, so that a dominant input into the density of states at EF and, therefore, to the conductivity is provided not by the interface states, but by the surface bands of the net layered system. It is reasonable therefore to consider an alternative interpretation of the reported thickness dependence of the conductivity of the system, such as the possible surface segregation of components or unavoidable contaminations, which seems much more realistic than the interpretation based on involving topological insulators and topologically protected surface states.
publisher Publishing house "Academperiodika"
publishDate 2021
url https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2020235
work_keys_str_mv AT yakovkinin surfaceandinterfacebandsofthecdtehgtecdteheterostructureevidenceofmetallicity
AT yakovkinin poverhnevitainterfejsnizonigeterostrukturicdtehgtecdtedokazimetalevosti
first_indexed 2025-08-07T04:13:46Z
last_indexed 2025-08-07T04:13:46Z
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