Robust midgap states in band-inverted junctions under electric and magnetic fields
Several IV–VI semiconductor compounds made of heavy atoms, such as Pb1−xSnxTe, may undergo band-inversion at the L point of the Brillouin zone upon variation of their chemical composition. This inversion gives rise to topologically distinct phases, characterized by a change in a topological invarian...
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doaj-32959bcb13864faca37555ac5d83c7a92020-11-25T01:26:13ZengBeilstein-InstitutBeilstein Journal of Nanotechnology2190-42862018-05-01911405141310.3762/bjnano.9.1332190-4286-9-133Robust midgap states in band-inverted junctions under electric and magnetic fieldsÁlvaro Díaz-Fernández0Natalia del Valle1Francisco Domínguez-Adame2GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid, SpainGISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid, SpainGISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid, SpainSeveral IV–VI semiconductor compounds made of heavy atoms, such as Pb1−xSnxTe, may undergo band-inversion at the L point of the Brillouin zone upon variation of their chemical composition. This inversion gives rise to topologically distinct phases, characterized by a change in a topological invariant. In the framework of the k·p theory, band-inversion can be viewed as a change of sign of the fundamental gap. A two-band model within the envelope-function approximation predicts the appearance of midgap interface states with Dirac cone dispersions in band-inverted junctions, namely, when the gap changes sign along the growth direction. We present a thorough study of these interface electron states in the presence of crossed electric and magnetic fields, the electric field being applied along the growth direction of a band-inverted junction. We show that the Dirac cone is robust and persists even if the fields are strong. In addition, we point out that Landau levels of electron states lying in the semiconductor bands can be tailored by the electric field. Tunable devices are thus likely to be realizable, exploiting the properties studied herein.https://doi.org/10.3762/bjnano.9.133crystalline topological insulatorselectric and magnetic fieldsLandau levelsmidgap states |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Álvaro Díaz-Fernández Natalia del Valle Francisco Domínguez-Adame |
spellingShingle |
Álvaro Díaz-Fernández Natalia del Valle Francisco Domínguez-Adame Robust midgap states in band-inverted junctions under electric and magnetic fields Beilstein Journal of Nanotechnology crystalline topological insulators electric and magnetic fields Landau levels midgap states |
author_facet |
Álvaro Díaz-Fernández Natalia del Valle Francisco Domínguez-Adame |
author_sort |
Álvaro Díaz-Fernández |
title |
Robust midgap states in band-inverted junctions under electric and magnetic fields |
title_short |
Robust midgap states in band-inverted junctions under electric and magnetic fields |
title_full |
Robust midgap states in band-inverted junctions under electric and magnetic fields |
title_fullStr |
Robust midgap states in band-inverted junctions under electric and magnetic fields |
title_full_unstemmed |
Robust midgap states in band-inverted junctions under electric and magnetic fields |
title_sort |
robust midgap states in band-inverted junctions under electric and magnetic fields |
publisher |
Beilstein-Institut |
series |
Beilstein Journal of Nanotechnology |
issn |
2190-4286 |
publishDate |
2018-05-01 |
description |
Several IV–VI semiconductor compounds made of heavy atoms, such as Pb1−xSnxTe, may undergo band-inversion at the L point of the Brillouin zone upon variation of their chemical composition. This inversion gives rise to topologically distinct phases, characterized by a change in a topological invariant. In the framework of the k·p theory, band-inversion can be viewed as a change of sign of the fundamental gap. A two-band model within the envelope-function approximation predicts the appearance of midgap interface states with Dirac cone dispersions in band-inverted junctions, namely, when the gap changes sign along the growth direction. We present a thorough study of these interface electron states in the presence of crossed electric and magnetic fields, the electric field being applied along the growth direction of a band-inverted junction. We show that the Dirac cone is robust and persists even if the fields are strong. In addition, we point out that Landau levels of electron states lying in the semiconductor bands can be tailored by the electric field. Tunable devices are thus likely to be realizable, exploiting the properties studied herein. |
topic |
crystalline topological insulators electric and magnetic fields Landau levels midgap states |
url |
https://doi.org/10.3762/bjnano.9.133 |
work_keys_str_mv |
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1725110077153607680 |