First Principles study of transport properties 1T’- WTe₂monolayer

2D transition metal dichalcogenides have drawn special attention to due to their spintronic and valleytronic properties over the past decade. Intriguing physical properties emerge from 1T’-WTe₂monolayer, is a topological insulator and exhibits quantized spin hall conductance up to a record-high phase transition temperature of 100 K. 1T’-WTe₂ sheets exhibit a band gap below 100K, but are metallic above. We investigate charge and spin transport in 1T’-WTe₂ monolayer in semimetal and semiconductor phases at finite temperatures. We applied our recently-developed first-principles density matrix dynamics (FPDM) with ab initio electron-phonon and electron-impurity scattering and self-consistent spin-orbit coupling [1].  We find the spin lifetime increases with reducing temperature in both phases. Predicted mobility in the semiconducting phase agrees reasonably with experimental measurements. Spin and carrier lifetimes are linearly proportional, according to the Elliot-Yafet (EY) mechanism. Under an external electric field, spin relaxation shows a distinct character that deviates from both the EY and D'yakonov-Perel' mechanisms. Our FPDM method provides insights into spin relaxation in 2D quantum materials beyond the traditional mechanistic regimes.

[1] J. Xu et al, Phys. Rev. B, 2021.