Speaker
Description
Bulk orthorhombic T$_d$-MoTe$_2$ is a type-II Weyl semimetal and becomes superconducting at a critical temperature of $T_c = 0.1\,\text{K}$. Remarkably, superconductivity becomes far more robust in the 2D limit, contrary to generic models and the established trend in ultrathin metal films. Recent transport measurements reported a gradual increase in $T_c$ as the thickness is reduced with $T_c$ reaching 7.6 K in the monolayer. The reasons for the strong increase in $T_c$ as well as the nature of the superconducting state remain unknown. Here, we present the electronic structure of exfoliated mono- and bilayer T$_d$-MoTe$_2$ probed by micro-focused angle resolved photoemission spectroscopy. Our thickness-dependent measurements reveal that mono- and bilayer MoTe$_2$ are both compensated metals. The electron pocket of monolayer MoTe$_2$, shows signatures of strong coupling to optical phonons with a mass enhancement $\lambda\approx 1.5$. In bilayer MoTe2 electron-phonon coupling is weaker consistent with the thickness dependence of $T_c$.
