Surface-dependent Majorana vortex phases in topological crystalline insulators

Fuente: arXiv
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Main Authors: Luo, Xun-Jiang, Pan, Xiao-Hong, Shi, Yilin, Wu, Fengcheng
Format: Preprint
Published: 2025
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author Luo, Xun-Jiang
Pan, Xiao-Hong
Shi, Yilin
Wu, Fengcheng
author_facet Luo, Xun-Jiang
Pan, Xiao-Hong
Shi, Yilin
Wu, Fengcheng
contents The topological crystalline insulator SnTe exhibits two types of surface Dirac cones: one located at non-time-reversal-invariant momenta on the (001) and (110) surfaces, and the other at time-reversal-invariant momenta on the (111) surface. Motivated by the recent experimental evidence of Majorana vortex end modes (MVEMs) and their hybridization on the (001) surface [Nature 633, 71 (2024)], we present a comprehensive investigation of Majorana vortex phases in SnTe, including topological classification, surface-state Hamiltonians analysis, and lattice model calculations. By utilizing rotational and magnetic mirror symmetries, we present two equivalent methods to reveal the topology of Majorana phases on different surfaces. We find that the MVEMs on the (001) and (110) surfaces are protected by both magnetic group and rotational symmetries. In contrast, the MVEMs on the (111) surface are protected by magnetic group or particle-hole symmetry. Due to the different properties of Dirac fermions in the $\barΓ$ and $\bar{M}$ valleys on the (111) surfaces, including Fermi velocities and energy levels, we find that abundant vortex phase transitions can occur for the [111]-direction vortex. As the chemical potential increases, the number of robust MVEMs can change from $0\rightarrow 1\rightarrow 2$. These vortex transitions are characterized by both $Z$ winding number and $Z_2$ pfaffian topological invariants.
format Preprint
id arxiv_https___arxiv_org_abs_2501_03868
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Surface-dependent Majorana vortex phases in topological crystalline insulators
Luo, Xun-Jiang
Pan, Xiao-Hong
Shi, Yilin
Wu, Fengcheng
Superconductivity
The topological crystalline insulator SnTe exhibits two types of surface Dirac cones: one located at non-time-reversal-invariant momenta on the (001) and (110) surfaces, and the other at time-reversal-invariant momenta on the (111) surface. Motivated by the recent experimental evidence of Majorana vortex end modes (MVEMs) and their hybridization on the (001) surface [Nature 633, 71 (2024)], we present a comprehensive investigation of Majorana vortex phases in SnTe, including topological classification, surface-state Hamiltonians analysis, and lattice model calculations. By utilizing rotational and magnetic mirror symmetries, we present two equivalent methods to reveal the topology of Majorana phases on different surfaces. We find that the MVEMs on the (001) and (110) surfaces are protected by both magnetic group and rotational symmetries. In contrast, the MVEMs on the (111) surface are protected by magnetic group or particle-hole symmetry. Due to the different properties of Dirac fermions in the $\barΓ$ and $\bar{M}$ valleys on the (111) surfaces, including Fermi velocities and energy levels, we find that abundant vortex phase transitions can occur for the [111]-direction vortex. As the chemical potential increases, the number of robust MVEMs can change from $0\rightarrow 1\rightarrow 2$. These vortex transitions are characterized by both $Z$ winding number and $Z_2$ pfaffian topological invariants.
title Surface-dependent Majorana vortex phases in topological crystalline insulators
topic Superconductivity
url https://arxiv.org/abs/2501.03868