Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://www.teses.usp.br/teses/disponiveis/43/43134/tde-12102022-091545/ |
Resumo: | The challenges inherent to the research of topological insulators in two dimensions based on HgTe/CdTe quantum wells have spurred the search for alternative platforms to study systems exhibiting the quantum Hall effect of spin. In this context, InAs/GaSb semiconductor quantum wells stand out as an alternative. In this work, we focus on the transport properties in InAs/GaSb quantum well systems in the topological regime. Using an effective Hamiltonian obtained from the kp-formalism, it was possible to develop tight-binding models for different heterostructure configurations (double and triple wells) based on the set of sites in the discretized position space. Using this model, it was possible to calculate the transport properties in different InAs/GaSb nanostructures by numerical calculations with the KWANT package. In the case of double InAs/GaSb wells, we show the topological transition and the formation of edge states by setting the value of a perpendicular electric field. In particular, oscillations occur in the energy gap as a function of the field, indicating an experimentally measurable signature of the formation of topological edge states. Moreover, for symmetric GaSb/InAs/GaSb triple-well systems, our results show the formation of circular current patterns when the Fermi energy is at the threshold between the bulk bands and the Dirac cone. Since the formation of these circular current patterns coincides with pronounced conductivity peaks, this phenomenon can be associated with the Fabry-Pérot effect. In addition to the main work, the formation of excitons in dichalcogenide monolayers of transition metals was also studied, as well as the phenomenon known as \\emph{weak localization} in graphene functionalized with the addition of hydrogen atoms, both works resulting from a stay in the group of prof. Jaroslav Fabian at the University of Regensburg. |
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Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wellsTransporte eletrônico e efeito Hall quântico de spin em poços quânticos de InAs/GaSbAdatomsComputational PhysicsEfeito Hall de quântico spineffective modelExcitonexcitonsFormalismo de LandauergrafenoGrapheneisolantes topológicoskp-modelKwantLandauer\'s formalismQSHEquantum transportspintronicTopological InsulatorThe challenges inherent to the research of topological insulators in two dimensions based on HgTe/CdTe quantum wells have spurred the search for alternative platforms to study systems exhibiting the quantum Hall effect of spin. In this context, InAs/GaSb semiconductor quantum wells stand out as an alternative. In this work, we focus on the transport properties in InAs/GaSb quantum well systems in the topological regime. Using an effective Hamiltonian obtained from the kp-formalism, it was possible to develop tight-binding models for different heterostructure configurations (double and triple wells) based on the set of sites in the discretized position space. Using this model, it was possible to calculate the transport properties in different InAs/GaSb nanostructures by numerical calculations with the KWANT package. In the case of double InAs/GaSb wells, we show the topological transition and the formation of edge states by setting the value of a perpendicular electric field. In particular, oscillations occur in the energy gap as a function of the field, indicating an experimentally measurable signature of the formation of topological edge states. Moreover, for symmetric GaSb/InAs/GaSb triple-well systems, our results show the formation of circular current patterns when the Fermi energy is at the threshold between the bulk bands and the Dirac cone. Since the formation of these circular current patterns coincides with pronounced conductivity peaks, this phenomenon can be associated with the Fabry-Pérot effect. In addition to the main work, the formation of excitons in dichalcogenide monolayers of transition metals was also studied, as well as the phenomenon known as \\emph{weak localization} in graphene functionalized with the addition of hydrogen atoms, both works resulting from a stay in the group of prof. Jaroslav Fabian at the University of Regensburg.Os desafios inerentes à pesquisa de isolantes topológicos em duas dimensões baseados em poços quânticos de HgTe/CdTe têm fomentado a busca por plataformas alternativas para se estudar sistemas que apresentem o efeito Hall quântico de spin. Neste contexto, poços quânticos semicondutores de InAs/GaSb se destacam como alternativa. Neste trabalho, focamos nas propriedades de transporte em sistemas de poços quânticos de InAs/GaSb no regime topológico. Utilizando um Hamiltoniano efetivo, obtido a partir do formalismo kp, foi possível desenvolver modelos tight-binding para diferentes heteroestruturas (poços duplos e triplos) usando como base o conjunto dos sítios do espaço de posições discretizado . A partir desse modelo pôde-se calcular propriedades de transporte em nanoestruturas de InAs/GaSb por meio de cálculos numéricos com o pacote KWANT. No caso de poços duplos InAs/GaSb, mostramos a transição topológica e formação de estados de borda ajustando o valor de um campo elétrico perpendicular. Notavelmente, aparecem oscilações no gap de energia em função do campo, indicando uma assinatura da formação de estados de borda topológicos que pode ser medida experimentalmente. Nossos resultados para sistemas de poços triplos simétricos GaSb/InAs/GaSb também mostram a formação de padrões circulares de corrente quando a energia de Fermi é posicionada no limiar entre as bandas do tipo-bulk e o cone de Dirac. Como a formação desses padrões circulares de corrente coincide com picos na condutância, pode-se associar tal fenômeno ao efeito do tipo Fabry-Pérot. Além do trabalho principal, investigou-se também a formação de excitons em monocamadas dicalcogenetos de metais de transição bem como o fenômeno conhecido por localização fraca em grafeno funcionalizado com a adição de átomos de Hidrogênio, ambos os trabalhos resultantes de um período de estadia no grupo do prof. Jaroslav Fabian na Universidade de Regensburg.Biblioteca Digitais de Teses e Dissertações da USPSilva, Luis Gregorio Godoy de Vasconcellos Dias daMedeiros, Marcos Henrique Lima de2022-08-04info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/43/43134/tde-12102022-091545/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2022-12-16T16:37:49Zoai:teses.usp.br:tde-12102022-091545Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212022-12-16T16:37:49Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells Transporte eletrônico e efeito Hall quântico de spin em poços quânticos de InAs/GaSb |
title |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells |
spellingShingle |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells Medeiros, Marcos Henrique Lima de Adatoms Computational Physics Efeito Hall de quântico spin effective model Exciton excitons Formalismo de Landauer grafeno Graphene isolantes topológicos kp-model Kwant Landauer\'s formalism QSHE quantum transport spintronic Topological Insulator |
title_short |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells |
title_full |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells |
title_fullStr |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells |
title_full_unstemmed |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells |
title_sort |
Electronic transport and quantum spin Hall effect in InAs/GaSb quantum wells |
author |
Medeiros, Marcos Henrique Lima de |
author_facet |
Medeiros, Marcos Henrique Lima de |
author_role |
author |
dc.contributor.none.fl_str_mv |
Silva, Luis Gregorio Godoy de Vasconcellos Dias da |
dc.contributor.author.fl_str_mv |
Medeiros, Marcos Henrique Lima de |
dc.subject.por.fl_str_mv |
Adatoms Computational Physics Efeito Hall de quântico spin effective model Exciton excitons Formalismo de Landauer grafeno Graphene isolantes topológicos kp-model Kwant Landauer\'s formalism QSHE quantum transport spintronic Topological Insulator |
topic |
Adatoms Computational Physics Efeito Hall de quântico spin effective model Exciton excitons Formalismo de Landauer grafeno Graphene isolantes topológicos kp-model Kwant Landauer\'s formalism QSHE quantum transport spintronic Topological Insulator |
description |
The challenges inherent to the research of topological insulators in two dimensions based on HgTe/CdTe quantum wells have spurred the search for alternative platforms to study systems exhibiting the quantum Hall effect of spin. In this context, InAs/GaSb semiconductor quantum wells stand out as an alternative. In this work, we focus on the transport properties in InAs/GaSb quantum well systems in the topological regime. Using an effective Hamiltonian obtained from the kp-formalism, it was possible to develop tight-binding models for different heterostructure configurations (double and triple wells) based on the set of sites in the discretized position space. Using this model, it was possible to calculate the transport properties in different InAs/GaSb nanostructures by numerical calculations with the KWANT package. In the case of double InAs/GaSb wells, we show the topological transition and the formation of edge states by setting the value of a perpendicular electric field. In particular, oscillations occur in the energy gap as a function of the field, indicating an experimentally measurable signature of the formation of topological edge states. Moreover, for symmetric GaSb/InAs/GaSb triple-well systems, our results show the formation of circular current patterns when the Fermi energy is at the threshold between the bulk bands and the Dirac cone. Since the formation of these circular current patterns coincides with pronounced conductivity peaks, this phenomenon can be associated with the Fabry-Pérot effect. In addition to the main work, the formation of excitons in dichalcogenide monolayers of transition metals was also studied, as well as the phenomenon known as \\emph{weak localization} in graphene functionalized with the addition of hydrogen atoms, both works resulting from a stay in the group of prof. Jaroslav Fabian at the University of Regensburg. |
publishDate |
2022 |
dc.date.none.fl_str_mv |
2022-08-04 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.teses.usp.br/teses/disponiveis/43/43134/tde-12102022-091545/ |
url |
https://www.teses.usp.br/teses/disponiveis/43/43134/tde-12102022-091545/ |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
|
dc.rights.driver.fl_str_mv |
Liberar o conteúdo para acesso público. info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Liberar o conteúdo para acesso público. |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.coverage.none.fl_str_mv |
|
dc.publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Biblioteca Digital de Teses e Dissertações da USP |
collection |
Biblioteca Digital de Teses e Dissertações da USP |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
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