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Composition and temperature-dependent phase transition in miscible Mo1-xWxTe2 single crystals
Yang-Yang Lv1, Lin Cao1, Xiao Li2
1National Laboratory of Solid State Microstructures &Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 China.
Scientific Reports
|March 16, 2017
Summary
Researchers synthesized tunable Mo1-xWxTe2 crystals, transitioning from semiconductor to semimetal behavior. This work maps phase diagrams and controls structural phases for exploring type-II Weyl semimetals.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Solid State Chemistry
Background:
- Transition metal dichalcogenides (TMDs) like WTe2 and MoTe2 are investigated for their potential as type-II Weyl semimetals.
- The orthorhombic Td phase is particularly significant for these topological properties.
Purpose of the Study:
- To synthesize and characterize a series of miscible Mo1-xWxTe2 single crystals.
- To investigate the influence of W content and temperature on the crystal structure and electrical properties.
- To establish a phase diagram for the Mo1-xWxTe2 system.
Main Methods:
- Bromine vapor transport method for crystal synthesis.
- Composition-dependent X-ray diffraction and Raman spectroscopy for structural analysis.
- Composition and temperature-dependent resistivity measurements for electrical property evaluation.
Main Results:
- Tunable crystal structures (hexagonal 2H, monoclinic β, orthorhombic Td) were achieved by varying W content.
- Electrical properties evolved from semiconductor to semimetal behavior with increasing W content.
- Temperature was found to induce structural phase transitions from β to Td phase.
Conclusions:
- A comprehensive phase diagram detailing temperature and composition dependencies was established for Mo1-xWxTe2.
- The study provides a method for controlling structural phases, crucial for exploring type-II Weyl semimetals and topological phase transitions.
- Key electrical parameters including carrier type, concentration, and mobility were determined.
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