Abstract
Transition metal dichalcogenides (TMDs) WTe2 and MoTe2 with orthorhombic Td phase, being potential candidates as type-II Weyl semimetals, are attracted much attention recently. Here we synthesized a series of miscible Mo1−xWxTe2 single crystals by bromine vapor transport method. Composition-dependent X-ray diffraction and Raman spectroscopy, as well as composition and temperature-dependent resistivity prove that the tunable crystal structure (from hexagonal (2H), monoclinic (β) to orthorhombic (Td) phase) can be realized by increasing W content in Mo1−xWxTe2. Simultaneously the electrical property gradually evolves from semiconductor to semimetal behavior. Temperature-dependent Raman spectroscopy proves that temperature also can induce the structural phase transition from β to Td phase in Mo1−xWxTe2 crystals. Based on aforementioned characterizations, we map out the temperature and composition dependent phase diagram of Mo1−xWxTe2 system. In addition, a series of electrical parameters, such as carrier type, carrier concentration and mobility, have also been presented. This work offers a scheme to accurately control structural phase in Mo1−xWxTe2 system, which can be used to explore type-II Weyl semimetal, as well as temperature/composition controlled topological phase transition therein.
Highlights
Continuously tuned by alloy[9,10,11,12]
As for the Mo1−xWxTe2 system, there are some experimental studies on ceramic samples[35,36] and theoretical predictions on monolayers[37,38], but no any phase-transitions works for single crystal samples at present, to the best of our knowledge
A series of Mo1−xWxTe2 single crystals were prepared by the chemical vapor transport (CVT) method that is discussed in detail elsewhere[39]
Summary
Continuously tuned by alloy[9,10,11,12]. While, MoTe2 compounds with βand Td phase show the metallic conductivity. It should be emphasized that both MoTe2 and WTe2 with Td phase belong to a type-II topological Weyl semimetal according to recent theoretical predictions[17,18]. Based on above-mentioned discussions, it is quite crucial to map out the phase diagram of Mo1−xWxTe2 at different temperature and their corresponding electrical properties in order to explore the type-II topological Weyl semimetals and corresponding novel physical properties in this system. The composition-dependent and temperature-dependent phase evolutions in Mo1−xWxTe2 are determined by Raman spectroscopic characterization. The electrical properties gradually evolve from semiconductor to semimetal behavior revealed by temperature-dependent resistivity and Hall curves Based on these data, we map out the composition- and temperature-dependent phase diagram of Mo1−xWxTe2 system
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
