Emerging Nontrivial Topology in Ultrathin Films of Rare-Earth Pnictides.
ACS Nano
; 17(21): 20991-20998, 2023 Nov 14.
Article
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| MEDLINE
| ID: mdl-37870504
ABSTRACT
Thin films of rare-earth monopnictide (RE-V) semimetals are expected to turn into semiconductors due to quantum confinement effects (QCE), lifting the overlap between electron pockets at Brillouin zone edges (X) and hole pockets at the zone center (Γ). Instead, using LaSb as an example, we find the emergence of the quantum spin Hall (QSH) insulator phase in (001)-oriented films as the thickness is reduced to 7, 5, or 3 monolayers (MLs). This is attributed to a strong QCE on the in-plane electron pockets and the lack of quantum confinement on the out-of-plane pocket projected onto the zone center, resulting in a band inversion. Spin-orbit coupling (SOC) opens a sizable nontrivial gap in the band structure of ultrathin films. Such effect is anticipated to be general in rare-earth monopnictides and may lead to interesting phenomena when coupled with the 4f magnetic moments present in other members of this family of materials.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
ACS Nano
Año:
2023
Tipo del documento:
Article
País de afiliación:
Estados Unidos