Dual topology and edge-reconstruction in $α$-Sn

Fuente: arXiv
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Auteurs principaux: Skolimowski, Jan, Nguyen, Nguyen Minh, Cuono, Giuseppe, Autieri, Carmine, Brzezicki, Wojciech
Format: Preprint
Publié: 2025
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author Skolimowski, Jan
Nguyen, Nguyen Minh
Cuono, Giuseppe
Autieri, Carmine
Brzezicki, Wojciech
author_facet Skolimowski, Jan
Nguyen, Nguyen Minh
Cuono, Giuseppe
Autieri, Carmine
Brzezicki, Wojciech
contents We formulate the tight-binding model for cubic $α$-Sn based on the DFT calculations. In the model, we incorporate a variable bond angle, which allows us to simulate the effect of the in-plane strain. In the bulk, we demonstrate the presence of the $\mathbb{Z}_2$ topological invariant and a non-zero mirror Chern number, making $α$-Sn one of the rare cases where dual topology can be observed. We calculate the topological phase diagram of multi-layer $α$-Sn as a function of strain and number of layers. We find that a non-trivial quantum spin Hall state appears only for compressive strain above five layers of thickness. Quite surprisingly, both in the trivial and non-trivial phases, we find a plethora of edge-states with energies inside the bulk gap of the system. Some of these states are localized at the side surfaces of the slab, some of them prefer top/bottom surfaces and some are localized in the hinges. We trace the microscopic origin of these states back to a minimal model that supports chiral symmetry and multiple one-dimensional winding numbers that take different values in different directions in the Brillouin zone.
format Preprint
id arxiv_https___arxiv_org_abs_2511_23289
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dual topology and edge-reconstruction in $α$-Sn
Skolimowski, Jan
Nguyen, Nguyen Minh
Cuono, Giuseppe
Autieri, Carmine
Brzezicki, Wojciech
Mesoscale and Nanoscale Physics
Materials Science
We formulate the tight-binding model for cubic $α$-Sn based on the DFT calculations. In the model, we incorporate a variable bond angle, which allows us to simulate the effect of the in-plane strain. In the bulk, we demonstrate the presence of the $\mathbb{Z}_2$ topological invariant and a non-zero mirror Chern number, making $α$-Sn one of the rare cases where dual topology can be observed. We calculate the topological phase diagram of multi-layer $α$-Sn as a function of strain and number of layers. We find that a non-trivial quantum spin Hall state appears only for compressive strain above five layers of thickness. Quite surprisingly, both in the trivial and non-trivial phases, we find a plethora of edge-states with energies inside the bulk gap of the system. Some of these states are localized at the side surfaces of the slab, some of them prefer top/bottom surfaces and some are localized in the hinges. We trace the microscopic origin of these states back to a minimal model that supports chiral symmetry and multiple one-dimensional winding numbers that take different values in different directions in the Brillouin zone.
title Dual topology and edge-reconstruction in $α$-Sn
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2511.23289