Doping-Induced Electronic and Structural Phase Transition in the Bulk Weyl Semimetal Mo1-xWxTe2

TL;DR

This study investigates how doping influences the electronic and structural phase transitions in bulk Mo1-xWxTe2, revealing topological surface states, phase transition temperature shifts, and the interplay between electronic properties and elastic deformations.

Contribution

It provides a comprehensive experimental and theoretical analysis of doping-induced phase transitions and topological states in Mo1-xWxTe2, combining multiple advanced techniques.

Findings

Doping increases the phase transition temperature from 230 K to 270 K.

Surface electronic states indicative of topological Fermi arcs were observed.

Enhanced magnetoresistance and elastoresistance in the Td phase due to electron backscattering.

Abstract

A comprehensive study of the electronic and structural phase transition from 1T` to Td in the bulk Weyl semimetal Mo1-xWxTe2 at different doping concentrations has been carried out using time-of-flight momentum microscopy (including circular and linear dichroism), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron diffraction (XPD), X-ray diffraction (XRD), angle-resolved Raman spectroscopy, transport measurements, density functional theory (DFT) and Kikuchi pattern calculations. High-resolution angle-resolved photoemission spectroscopy (ARPES) at 20 K reveals surface electronic states, which are indicative of topological Fermi arcs. Their dispersion agrees with the position of Weyl points predicted by DFT calculations based on the experimental crystal structure of our samples determined by XRD. Raman spectroscopy confirms the inversion symmetry breaking for the Td -phase, which is a necessary condition for the emergence of topological states. Transport measurements show that increasing the doping concentration from 2 to 9% leads to an increase in the temperature of the phase transition from 1T` to Td from 230 K to 270 K. Magnetoresistance and longitudinal elastoresistance show significantly increased values in the Td -phase due to stimulated inter-pocket electron backscattering. The results demonstrate the close relationship between electronic properties and elastic deformations in MoTe2.