Thickness dependent electronic structure of exfoliated mono- and few-layer 1T′−MoTe2

Abstract

Semimetallic ${\mathrm{MoTe}}_{2}$ has recently generated enormous attention due to its topological properties, large magnetoresistance, superconductivity, suitability for homojunction phase patterning, and, in particular, metal-insulator transition of thin layers, possibly indicating a quantum spin hall state. These observations prove the potential of ${\mathrm{MoTe}}_{2}$ for thin film applications and call for systematic investigations of the thickness dependent electronic structure. Here we apply angle-resolved photoemission spectroscopy supported by band structure calculations to elucidate the electronic structure of exfoliated $1{\mathrm{T}}^{\ensuremath{'}}\text{\ensuremath{-}}{\mathrm{MoTe}}_{2}$. Electron and hole pockets of the inverted conduction and valence bands near $\mathrm{\ensuremath{\Gamma}}$ are resolved down to the monolayer. The Fermi level of exfoliated $1{\mathrm{T}}^{\ensuremath{'}}\text{\ensuremath{-}}{\mathrm{MoTe}}_{2}$ monolayers lays within the electron pockets indicating intrinsic $n$-type doping. ${E}_{F}$ shifts downward with increasing thickness consistent with a surface driven mechanism. Our study provides insight on the electronic properties of semimetallic $1{\mathrm{T}}^{\ensuremath{'}}\text{\ensuremath{-}}{\mathrm{MoTe}}_{2}$ as an indispensable ingredient for future thin film functionalization.