Topological phase transition between distinctWeyl semimetal states in MoTe2

TL;DR

This paper provides experimental evidence of a temperature-induced topological phase transition in MoTe2, revealing how structural and electronic properties change between distinct Weyl semimetal states, influenced by electron-phonon interactions.

Contribution

It demonstrates a novel temperature-driven topological phase transition in MoTe2, highlighting the role of electron-phonon coupling and sample conditions in topological state evolution.

Findings

Anomalies in Raman spectra indicate phase transition around 70 K.

Structural and thermodynamic measurements support the topological change.

Electron-phonon coupling is identified as the main mechanism driving the transition.

Abstract

We present experimental evidence of an intriguing phase transition between distinct topological states in the type-II Weyl semimetal MoTe2. We observe anomalies in the Raman phonon frequencies and linewidths as well as electronic quasielastic peaks around 70 K, which, together with structural, thermodynamic measurements, and electron-phonon coupling calculations, demonstrate a temperature-induced transition between two topological phases previously identified by contrasting spectroscopic measurements. An analysis of experimental data suggests electron-phonon coupling as the main driving mechanism for the change of key topological characters in the electronic structure of MoTe2.We also find the phase transition to be sensitive to sample conditions distinguished by synthesis methods. These discoveries of temperature and material condition-dependent topological phase evolutions and transitions in MoTe2 advance the fundamental understanding of the underlying physics and enable an effective approach to tuning Weyl semimetal states for technological applications.