Impact of domain disorder on optoelectronic properties of layered semimetal MoTe2

Abstract We address the impact of crystal phase disorder on the generation of helicity-dependent photocurrents in layered MoTe 2 , which is one of the van der Waals materials to realize the topological type-II Weyl semimetal phase. Using scanning photocurrent microscopy, we spatially probe the phase transition and its hysteresis between the centrosymmetric, monoclinic 1Tʹ phase to the symmetry-broken, orthorhombic T d phase as a function of temperature. We find a highly disordered photocurrent response in the intermediate temperature regime. Moreover, we demonstrate that helicity-dependent and ultrafast photocurrents in MoTe 2 arise most likely from a local breaking of the electronic symmetries. Our results highlight the prospects of local domain morphologies and ultrafast relaxation dynamics on the optoelectronic properties of low-dimensional van der Waals circuits.