Topological properties of the [110] SnTe nanowires

TL;DR

This paper explores the topological phases of [110] SnTe nanowires, revealing Weyl semimetal and topological insulator phases, and demonstrates the emergence of Majorana zero modes under certain conditions, highlighting their potential for quantum applications.

Contribution

It provides a detailed analysis of symmetry-protected topological states in [110] SnTe nanowires, including the effects of various fields and symmetry-breaking, and compares their topological phases to other orientations.

Findings

Identified Weyl semimetal phase protected by screw axis symmetry.

Discovered topological insulator phase with a $ ext{Z}$ invariant protected by mirror symmetry.

Showed Majorana zero modes can be realized more easily in [110] nanowires.

Abstract

SnTe materials are know to be a platform for realization of various strong and symmetry protected topological phases in one, two and three spatial dimensions. We study symmetry-protected topological states in $[110]$ SnTe nanowires in the presence of various combinations of Zeeman field, $s-$wave superconductivity, inversion-symmetry-breaking field and the thickness of the wire. In the normal state we find a Weyl semimetal phase protected by a twofold screw axis symmetry and a topological insulating phase characterized by a $\mathbb{Z}$ invariant protected by a mirror symmetry. In the presence of superconductivity, we find inversion-symmetry-protected gapless phase which becomes fully gapped and topologically non-trivial by introducing an inversion-symmetry-breaking field. Consequently, we find topologically protected localized Majorana zero modes appear at the ends of the wire. We find that this Majorana phase is much easier to achieve in a $[110]$ SnTe nanowire than in a $[001]$ one.