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

My recent density functional theory-based work on bilayer jacutingaite (Pt2HgSe3) is published in the journal Physical Review Materials!

Title: Gate-tunable imbalanced Kane-Mele model in encapsulated bilayer jacutingaite
Reference: Louk Rademaker and Marco Gibertini, Phys. Rev. Materials 5, 044201 (2021)
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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