Spontaneously broken chiral symmetry in the interacting Kane-Mele model

Fuente: arXiv
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Main Authors: Zeng, Minghuan, Zeng, Junjie, Qin, Ling, Feng, Shiping, Xu, Donghui, Wang, Rui
Format: Preprint
Published: 2025
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_version_ 1866908401982767104
author Zeng, Minghuan
Zeng, Junjie
Qin, Ling
Feng, Shiping
Xu, Donghui
Wang, Rui
author_facet Zeng, Minghuan
Zeng, Junjie
Qin, Ling
Feng, Shiping
Xu, Donghui
Wang, Rui
contents The essential properties of the half-filled interacting Kane-Mele model on a hexagon lattice is studied using the slave rotor approach. It is shown clearly that a long-range charge-order state with spontaneously broken chiral symmetry emerges in the weak and moderate interaction regimes, as well as a presumed site-selected topological Mott insulator state in the stronger interaction regime with U < UMott, where UMott is the critical interaction strength, and in the case of U > UMott, the system is transited into the usual topological Mott state. This new charge-order state has lower energy compared to the usual topological band insulator (TBI) state with chiral symmetry, and thus is named as non-chiral TBI state. More specifically, in this non-chiral TBI state without any long-range magnetic order, a long-range charge order with different electron occupation on two sublattices appears in the absence of external sublattice field. The spontaneously broken chiral symmetry gives rise to a special helical edge state, which has different spin accumulation on opposite edges of the cylinder with periodic boundary condition in the zigzag direction, and thus leads to a net spin current across the system. This net spin current would be further strengthened if the nearest neighbor electron Coulomb interaction is taken into account as well, because it is favorable for the long-range charge order with different electron occupation on sublattices.
format Preprint
id arxiv_https___arxiv_org_abs_2506_08322
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spontaneously broken chiral symmetry in the interacting Kane-Mele model
Zeng, Minghuan
Zeng, Junjie
Qin, Ling
Feng, Shiping
Xu, Donghui
Wang, Rui
Strongly Correlated Electrons
The essential properties of the half-filled interacting Kane-Mele model on a hexagon lattice is studied using the slave rotor approach. It is shown clearly that a long-range charge-order state with spontaneously broken chiral symmetry emerges in the weak and moderate interaction regimes, as well as a presumed site-selected topological Mott insulator state in the stronger interaction regime with U < UMott, where UMott is the critical interaction strength, and in the case of U > UMott, the system is transited into the usual topological Mott state. This new charge-order state has lower energy compared to the usual topological band insulator (TBI) state with chiral symmetry, and thus is named as non-chiral TBI state. More specifically, in this non-chiral TBI state without any long-range magnetic order, a long-range charge order with different electron occupation on two sublattices appears in the absence of external sublattice field. The spontaneously broken chiral symmetry gives rise to a special helical edge state, which has different spin accumulation on opposite edges of the cylinder with periodic boundary condition in the zigzag direction, and thus leads to a net spin current across the system. This net spin current would be further strengthened if the nearest neighbor electron Coulomb interaction is taken into account as well, because it is favorable for the long-range charge order with different electron occupation on sublattices.
title Spontaneously broken chiral symmetry in the interacting Kane-Mele model
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2506.08322