Band structure and end states in InAs/GaSb core-shell-shell nanowires
(2020) In Physical Review B 102(19).- Abstract
Quantum wells in InAs/GaSb heterostructures can be tuned to a topological regime associated with the quantum spin Hall effect, which arises due to an inverted band gap and hybridized electron and hole states. Here, we investigate electron-hole hybridization and the fate of the quantum spin Hall effect in a quasi-one-dimensional geometry, realized in a core-shell-shell nanowire with an insulator core and InAs and GaSb shells. We calculate the band structure for an infinitely long nanowire using k·p theory within the Kane model and the envelope function approximation, then map the result onto a Bernevig-Hughes-Zhang model which is used to investigate finite-length wires. Clearly, quantum spin Hall edge states cannot appear in the... (More)
Quantum wells in InAs/GaSb heterostructures can be tuned to a topological regime associated with the quantum spin Hall effect, which arises due to an inverted band gap and hybridized electron and hole states. Here, we investigate electron-hole hybridization and the fate of the quantum spin Hall effect in a quasi-one-dimensional geometry, realized in a core-shell-shell nanowire with an insulator core and InAs and GaSb shells. We calculate the band structure for an infinitely long nanowire using k·p theory within the Kane model and the envelope function approximation, then map the result onto a Bernevig-Hughes-Zhang model which is used to investigate finite-length wires. Clearly, quantum spin Hall edge states cannot appear in the core-shell-shell nanowires which lack one-dimensional edges, but in the inverted band gap regime we find that the finite-length wires instead host localized states at the wire ends. These end states are not topologically protected; they are fourfold degenerate and split into two Kramers pairs in the presence of potential disorder along the axial direction. However, there is some remnant of the topological protection of the quantum spin Hall edge states in the sense that the end states are fully robust to (time-reversal preserving) angular disorder, as long as the bulk band gap is not closed.
(Less)
- author
- Viñas Boström, Florinda LU ; Tsintzis, Athanasios LU ; Hell, Michael LU and Leijnse, Martin LU
- organization
- publishing date
- 2020
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Review B
- volume
- 102
- issue
- 19
- article number
- 195434
- publisher
- American Physical Society
- external identifiers
-
- scopus:85097184939
- ISSN
- 2469-9950
- DOI
- 10.1103/PhysRevB.102.195434
- language
- English
- LU publication?
- yes
- id
- 75ee7d38-b650-4441-8af0-b49f8098a872
- date added to LUP
- 2020-12-15 10:25:14
- date last changed
- 2024-01-17 18:44:57
@article{75ee7d38-b650-4441-8af0-b49f8098a872,
abstract = {{<p>Quantum wells in InAs/GaSb heterostructures can be tuned to a topological regime associated with the quantum spin Hall effect, which arises due to an inverted band gap and hybridized electron and hole states. Here, we investigate electron-hole hybridization and the fate of the quantum spin Hall effect in a quasi-one-dimensional geometry, realized in a core-shell-shell nanowire with an insulator core and InAs and GaSb shells. We calculate the band structure for an infinitely long nanowire using k·p theory within the Kane model and the envelope function approximation, then map the result onto a Bernevig-Hughes-Zhang model which is used to investigate finite-length wires. Clearly, quantum spin Hall edge states cannot appear in the core-shell-shell nanowires which lack one-dimensional edges, but in the inverted band gap regime we find that the finite-length wires instead host localized states at the wire ends. These end states are not topologically protected; they are fourfold degenerate and split into two Kramers pairs in the presence of potential disorder along the axial direction. However, there is some remnant of the topological protection of the quantum spin Hall edge states in the sense that the end states are fully robust to (time-reversal preserving) angular disorder, as long as the bulk band gap is not closed.</p>}},
author = {{Viñas Boström, Florinda and Tsintzis, Athanasios and Hell, Michael and Leijnse, Martin}},
issn = {{2469-9950}},
language = {{eng}},
number = {{19}},
publisher = {{American Physical Society}},
series = {{Physical Review B}},
title = {{Band structure and end states in InAs/GaSb core-shell-shell nanowires}},
url = {{http://dx.doi.org/10.1103/PhysRevB.102.195434}},
doi = {{10.1103/PhysRevB.102.195434}},
volume = {{102}},
year = {{2020}},
}