# Appearance of T$_d^*$ phase across the T$_{d}$-1T$^{\prime}$ phase boundary in Weyl semimetal MoTe$_{2}$

## TL;DR

This study investigates the T$_{d}^{*}$ phase in MoTe$_{2}$, revealing its unique stacking order and its emergence during warming from the T$_{d}$ phase, providing insights into phase transitions in Weyl semimetals.

## Contribution

It uncovers the detailed stacking sequence and temperature-dependent behavior of the T$_{d}^{*}$ phase in MoTe$_{2}$ using neutron scattering, highlighting its role in phase boundary dynamics.

## Key findings

- T$_{d}^{*}$ phase appears only on warming from T$_{d}$
- T$_{d}^{*}$ has an 'AABB' stacking sequence
- Diffuse scattering indicates frustrated stacking tendency during cooling

## Abstract

Using elastic neutron scattering on single crystals of MoTe$_{2}$ and Mo$_{1-x}$W$_{x}$Te$_{2}$ ($x \lesssim 0.01$), the temperature dependence of the recently discovered T$_{d}^{*}$ phase, present between the low temperature orthorhombic T$_{d}$ phase and high temperature monoclinic 1T$^{\prime}$ phase, is explored. The T$_{d}^{*}$ phase appears only on warming from T$_{d}$ and is observed in the hysteresis region prior to the 1T$^{\prime}$ transition. This phase consists of four layers in its unit cell, and is constructed by an "AABB" sequence of layer stacking operations rather than the "AB" and "AA" sequences of the 1T$^{\prime}$ and T$_{d}$ phases, respectively. Though the T$_{d}^{*}$ phase emerges without disorder on warming from T$_{d}$, on cooling from 1T$^{\prime}$ diffuse scattering is observed that suggests a frustrated tendency toward the "AABB" stacking.