Modelling near-surface bound electron states in a 3D topological insulator: analytical and numerical approaches

Autor:	V N Men'shov, V V Tugushev, T V Menshchikova, S V Eremeev, P M Echenique, E V Chulkov
Přispěvatelé:	Universidad del País Vasco, Eusko Jaurlaritza, Ministerio de Ciencia e Innovación (España), Ministry of Education and Science of the Russian Federation, Russian Foundation for Basic Research
Rok vydání:	2014
Předmět:	Topological insulator Materials science Condensed matter physics Band gap Insulator (electricity) Heterojunction Electron Interface states Condensed Matter Physics Overlayer Bound state General Materials Science Electronic band structure
Zdroj:	Digital.CSIC. Repositorio Institucional del CSIC instname
ISSN:	1361-648X
Popis:	We apply both analytical and ab-initio methods to explore heterostructures composed of a 3D topological insulator (3D TI) and an ultrathin normal insulator (NI) overlayer as a proving ground for the principles of topological phase engineering. Using the continual model of a semi-infinite 3D TI we study the surface potential (SP) effect caused by an attached ultrathin layer of 3D NI on the formation of topological bound states at the interface. The results reveal that the spatial profile and spectrum of these near-surface states strongly depend on both the sign and the strength of the SP. Using ab-initio band structure calculations to take the specificity of the materials into account, we investigate the NI/TI heterostructures formed by a single tetradymite-type quintuple or septuple layer block and the 3D TI substrate. The analytical continuum theory results relate the near-surface state evolution with the SP variation and are in good qualitative agreement with those obtained from density-functional theory (DFT) calculations. We also predict the appearance of the quasi-topological bound state on the 3D NI surface caused by a local band gap inversion induced by an overlayer. We acknowledge the partial support from the Basque Country Government, Departamento de Educacion, Universidades e Investigacion (Grant No. IT-756-13), the Spanish Ministerio de Ciencia e Innovacion (Grant No. FIS2010-19609-C02-01), the Ministry of Education and Science of the Russian Federation (No. 2.8575.2013) and the Russian Foundation for Basic Researches (grant 13-02-00016).
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d4c3f819ef4da980669f3dcd87aa1b3b https://pubmed.ncbi.nlm.nih.gov/25339457 Zobrazit plný text záznamu