<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>T</mml:mi><mml:mi>d</mml:mi></mml:msub></mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1</mml:mn><mml:msup><mml:mi>T</mml:mi><mml:mo>′</mml:mo></mml:msup></mml:mrow></mml:math> structural phase transition in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>WTe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> Weyl semimetal
Yu Tao, John Schneeloch, A. A. Aczel, Despina Louca
Abstract
Elastic neutron scattering on a single crystal combined with powder x-ray diffraction measurements were carried out to investigate how the crystal structure evolves as a function of temperature in the Weyl semimetal $\mathrm{W}{\mathrm{Te}}_{2}$. A sharp transition from the low-temperature orthorhombic phase (${T}_{d}$) to the high-temperature monoclinic phase ($1{T}^{\ensuremath{'}}$) was observed at ambient pressure in the single crystal near $\ensuremath{\sim}565$ K. Unlike in ${\mathrm{MoTe}}_{2}$, the solid-solid transition from ${T}_{d}$ to $1{T}^{\ensuremath{'}}$ occurs without the cell doubling of the intermediate ${T}_{d}^{*}$ phase with AABB (or ABBA) layer stacking. In powders, however, the thermal transition from the ${T}_{d}$ to the $1{T}^{\ensuremath{'}}$ phase was broadened and a two-phase coexistence was observed until 700 K, well above the structural transition.