Engineering the structural and electronic phases of MoTe2 through W substitution
Abstract
MoTe2 is an exfoliable transition metal dichalcogenide (TMD) which crystallizes in three symmetries, the semiconducting trigonal-prismatic 2H-phase, the semimetallic 1T monoclinic phase, and the semimetallic orthorhombic Td structure. The 2H-phase displays a band gap of 1 eV making it appealing for flexible and transparent optoelectronics. The Td-phase is predicted to possess unique topological properties which might lead to topologically protected non-dissipative transport channels. Recently, it was argued that it is possible to locally induce phase-transformations in TMDs, through chemical doping, local heating, or electric-field to achieve ohmic contacts or to induce useful functionalities such as electronic phase-change memory elements. The combination of semiconducting and topological elements based upon the same compound, might produce a new generation of high performance, low dissipation optoelectronic elements. Here, we show that it is possible to engineer the phases of MoTe2 through W substitution by unveiling the phase-diagram of the Mo1-xWxTe2 solid solution which displays a semiconducting to semimetallic transition as a function of x. We find that only 8 \% of W stabilizes the Td-phase at room temperature. Photoemission spectroscopy, indicates that this phase possesses a Fermi surface akin to that of WTe2.