Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2

TL;DR

This study uncovers novel domain-wall structures in MoTe2, revealing their potential to host topological interfacial states and demonstrating manipulation techniques, advancing understanding of topological phases in Weyl semimetals.

Contribution

It introduces the discovery of specific domain-wall structures in MoTe2 and explores their topological and conductive properties using advanced microscopy and calculations.

Findings

Polar domain walls can be manipulated with electron beams.

Phase domain walls form superlattice-like structures.

Possible conducting hinge states are observed at phase domain walls.

Abstract

Much of the dramatic growth in research on topological materials has focused on topologically protected surface states. While the domain walls of topological materials such as Weyl semimetals with broken inversion or time-reversal symmetry can provide a hunting ground for exploring topological interfacial states, such investigations have received little attention to date. Here, utilizing in-situ cryogenic transmission electron microscopy combined with first-principles calculations, we discover intriguing domain-wall structures in MoTe2, both between polar variants of the low-temperature(T) Weyl phase, and between this and the high-T high-order topological phase. We demonstrate how polar domain walls can be manipulated with electron beams and show that phase domain walls tend to form superlattice-like structures along the c axis. Scanning tunneling microscopy indicates a possible signature of a conducting hinge state at phase domain walls. Our results open avenues for investigating topological interfacial states and unveiling multifunctional aspects of domain walls in topological materials.