Studies of doping-driven structural phase transitions in (Mo,W)Te₂ using ARPES and XPS

(Mo,W)Te₂ may be a type-II Weyl semimetal when it is in a structural phase that breaks inversion symmetry. Previously, it has been shown that small amounts of surface electron doping in WTe₂ results in changes to surface electronic band structure that are consistent with a metastable shear displacement that locally restores inversion symmetry[1]. Here, we report progress on ARPES and XPS studies of the details of this phenomenon, including using higher temperatures to access states above the Fermi level, XPS to quantify the nature of the chemical changes, and composition-dependence to establish the ubiquity of this phenomenon in the (Mo,W)Te₂ series.

[1] Rossi, A., Resta, G., Lee, S., Redwing, R., Jozwiak, C., Bostwick, A., Rotenberg, E., Savrasov, S., & Vishik, I. (2020). Two phase transitions driven by surface electron doping in WTe2. Phys. Rev. B, 102, 121110.