We study free, capped, and encapsulated bilayer jacutingaite (Pt2HgSe3) from first principles. While the freestanding bilayer is a large-gap trivial insulator, we find that the encapsulated structure has a small trivial gap due to the competition between sublattice symmetry breaking and sublattice-dependent next-nearest-neighbor hopping. Upon the application of a small perpendicular electric field, the encapsulated bilayer undergoes a topological transition towards a quantum spin Hall insulator. We find that this topological transition can be qualitatively understood by modeling the two layers as uncoupled and can be described by an imbalanced Kane-Mele model that takes into account the sublattice imbalance and the corresponding inversion-symmetry breaking in each layer. Within this picture, bilayer jacutingaite undergoes a transition from a 0+0 state, where each layer is trivial, to a 0+1 state, where an unusual topological state relying on Rashba-like spin orbit coupling emerges in only one of the layers.

Gate-tunable imbalanced Kane-Mele model in encapsulated bilayer jacutingaite / Rademaker, L.; Gibertini, M.. - In: PHYSICAL REVIEW MATERIALS. - ISSN 2475-9953. - 5:4(2021), pp. 044201-044211. [10.1103/PhysRevMaterials.5.044201]

Gate-tunable imbalanced Kane-Mele model in encapsulated bilayer jacutingaite

Gibertini M.
2021-01-01

Abstract

We study free, capped, and encapsulated bilayer jacutingaite (Pt2HgSe3) from first principles. While the freestanding bilayer is a large-gap trivial insulator, we find that the encapsulated structure has a small trivial gap due to the competition between sublattice symmetry breaking and sublattice-dependent next-nearest-neighbor hopping. Upon the application of a small perpendicular electric field, the encapsulated bilayer undergoes a topological transition towards a quantum spin Hall insulator. We find that this topological transition can be qualitatively understood by modeling the two layers as uncoupled and can be described by an imbalanced Kane-Mele model that takes into account the sublattice imbalance and the corresponding inversion-symmetry breaking in each layer. Within this picture, bilayer jacutingaite undergoes a transition from a 0+0 state, where each layer is trivial, to a 0+1 state, where an unusual topological state relying on Rashba-like spin orbit coupling emerges in only one of the layers.
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Gate-tunable imbalanced Kane-Mele model in encapsulated bilayer jacutingaite / Rademaker, L.; Gibertini, M.. - In: PHYSICAL REVIEW MATERIALS. - ISSN 2475-9953. - 5:4(2021), pp. 044201-044211. [10.1103/PhysRevMaterials.5.044201]
Rademaker, L.; Gibertini, M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1247649
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