Topological characterization of modified Kane-Mele-Rashba models via local spin Chern marker

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Main Authors: Júnior, Sebastião dos Anjos Sousa, Ferraz, Marcus V. de S., de Lima, José P., Cysne, Tarik P.
Format: Preprint
Published: 2024
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author Júnior, Sebastião dos Anjos Sousa
Ferraz, Marcus V. de S.
de Lima, José P.
Cysne, Tarik P.
author_facet Júnior, Sebastião dos Anjos Sousa
Ferraz, Marcus V. de S.
de Lima, José P.
Cysne, Tarik P.
contents In this work, we use the local spin Chern marker (LSCM) recently introduced by Baù and Marrazzo [Phys. Rev. B 110, 054203 (2024)] to analyze the topology of the ground-state electronic wave functions in a finite honeycomb lattice flake described by three distinct models. The models considered here are characterized by strong Rashba spin-orbit interaction, which leads to non-conservation of the spin operator, i.e., $[\mathcal{H},\hat{s}_z]\neq 0$. The three spin-orbit couplings associated with the topological aspects of the models are: 1) Standard Kane-Mele coupling, 2) Sublattice-dependent Kane-Mele coupling, and 3) In-plane ($\hat{s}_y$) polarized Kane-Mele coupling. These couplings occur in graphene grown on suitable substrates and are relevant for modeling its van der Waals heterostructures. A particular topological phase diagram characterizes each of these spin-orbit interactions, and our calculations of LSCM successfully capture its general features. We also performed a detailed analysis of the spectral properties of the energy and valence-projected spin matrix eigenvalues, which shows that both exhibit a gap that protects the marker. Our results expand the applicability of the spin Chern number method to a class of Hamiltonians with experimental relevance and may contribute to future research on the real-space topology of realistic materials.
format Preprint
id arxiv_https___arxiv_org_abs_2409_02319
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Topological characterization of modified Kane-Mele-Rashba models via local spin Chern marker
Júnior, Sebastião dos Anjos Sousa
Ferraz, Marcus V. de S.
de Lima, José P.
Cysne, Tarik P.
Mesoscale and Nanoscale Physics
In this work, we use the local spin Chern marker (LSCM) recently introduced by Baù and Marrazzo [Phys. Rev. B 110, 054203 (2024)] to analyze the topology of the ground-state electronic wave functions in a finite honeycomb lattice flake described by three distinct models. The models considered here are characterized by strong Rashba spin-orbit interaction, which leads to non-conservation of the spin operator, i.e., $[\mathcal{H},\hat{s}_z]\neq 0$. The three spin-orbit couplings associated with the topological aspects of the models are: 1) Standard Kane-Mele coupling, 2) Sublattice-dependent Kane-Mele coupling, and 3) In-plane ($\hat{s}_y$) polarized Kane-Mele coupling. These couplings occur in graphene grown on suitable substrates and are relevant for modeling its van der Waals heterostructures. A particular topological phase diagram characterizes each of these spin-orbit interactions, and our calculations of LSCM successfully capture its general features. We also performed a detailed analysis of the spectral properties of the energy and valence-projected spin matrix eigenvalues, which shows that both exhibit a gap that protects the marker. Our results expand the applicability of the spin Chern number method to a class of Hamiltonians with experimental relevance and may contribute to future research on the real-space topology of realistic materials.
title Topological characterization of modified Kane-Mele-Rashba models via local spin Chern marker
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2409.02319