Paul Corbae, Aaron N. Engel, Jason T. Dong, Wilson J. Yánez-Parreño, Donghui Lu, Makoto Hashimoto, Alexei Fedorov, Christopher J. Palmstrøm
{"title":"Hybridization gap approaching the two-dimensional limit of topological insulator Bi$_x$Sb$_{1-x}$","authors":"Paul Corbae, Aaron N. Engel, Jason T. Dong, Wilson J. Yánez-Parreño, Donghui Lu, Makoto Hashimoto, Alexei Fedorov, Christopher J. Palmstrøm","doi":"arxiv-2409.11705","DOIUrl":null,"url":null,"abstract":"Bismuth antimony alloys (Bi$_x$Sb$_{1-x}$) provide a tuneable materials\nplatform to study topological transport and spin-polarized surface states\nresulting from the nontrivial bulk electronic structure. In the two-dimensional\nlimit, it is a suitable system to study the quantum spin Hall effect. In this\nwork we grow epitaxial, single orientation thin films of Bi$_x$Sb$_{1-x}$ on an\nInSb(111)B substrate down to two bilayers where hybridization effects should\ngap out the topological surface states. Supported by a tight-binding model,\nspin- and angle-resolved photoemission spectroscopy data shows pockets at the\nFermi level from the topological surface states disappear as the bulk gap\nincreases from confinement. Evidence for a gap opening in the topological\nsurface states is shown in the ultrathin limit. Finally, we observe\nspin-polarization approaching unity from the topological surface states in 10\nbilayer films. The growth and characterization of ultrathin Bi$_x$Sb$_{1-x}$\nalloys suggest ultrathin films of this material system can be used to study\ntwo-dimensional topological physics as well as applications such as topological\ndevices, low power electronics, and spintronics.","PeriodicalId":501234,"journal":{"name":"arXiv - PHYS - Materials Science","volume":"33 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Materials Science","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.11705","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Bismuth antimony alloys (Bi$_x$Sb$_{1-x}$) provide a tuneable materials
platform to study topological transport and spin-polarized surface states
resulting from the nontrivial bulk electronic structure. In the two-dimensional
limit, it is a suitable system to study the quantum spin Hall effect. In this
work we grow epitaxial, single orientation thin films of Bi$_x$Sb$_{1-x}$ on an
InSb(111)B substrate down to two bilayers where hybridization effects should
gap out the topological surface states. Supported by a tight-binding model,
spin- and angle-resolved photoemission spectroscopy data shows pockets at the
Fermi level from the topological surface states disappear as the bulk gap
increases from confinement. Evidence for a gap opening in the topological
surface states is shown in the ultrathin limit. Finally, we observe
spin-polarization approaching unity from the topological surface states in 10
bilayer films. The growth and characterization of ultrathin Bi$_x$Sb$_{1-x}$
alloys suggest ultrathin films of this material system can be used to study
two-dimensional topological physics as well as applications such as topological
devices, low power electronics, and spintronics.