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Pressure-Induced Phase Transition in Weyl Semimetallic WTe2
Juan Xia1, Dong-Fei Li2, Jia-Dong Zhou3
1Division of Physics and Applied Physics School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Small (Weinheim an Der Bergstrasse, Germany)
|August 29, 2017
Summary
Tungsten ditelluride (WTe2) single crystals undergo a structural phase transition under pressure, losing their Weyl semimetal states. This transition to a monoclinic phase also enables superconductivity in the material.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid-State Physics
Background:
- Tungsten ditelluride (WTe2) is a semimetal exhibiting unique properties like Weyl semimetal states, pressure-induced superconductivity, and giant magnetoresistance.
- The orthorhombic Td phase of WTe2 is known for its distinct electronic and vibrational characteristics.
Purpose of the Study:
- Investigate the high-pressure behavior of WTe2 single crystals.
- Understand the structural and electronic phase transitions under pressure.
- Explore the relationship between structural changes, Weyl states, and superconductivity.
Main Methods:
- High-pressure Raman microspectroscopy was employed to probe vibrational properties.
- Ab initio calculations were performed to understand the electronic structure and phase stability.
- Analysis of Raman peak shifts and vibrational anisotropy provided insights into structural changes.
Main Results:
- WTe2 single crystals exhibit significant plane-parallel/plane-vertical vibrational anisotropy.
- Raman peaks show a redshift under pressure, indicating structural instability of the Td phase.
- A phase transition from orthorhombic Td to monoclinic T' occurs at approximately 8 GPa.
Conclusions:
- The Td to T' phase transition in WTe2 leads to the vanishing of Weyl states due to the introduction of inversion symmetry.
- This pressure-induced transition offers a method for switching Weyl states without material doping.
- The emergence of the T' phase correlates with the onset of superconductivity in WTe2.
Keywords:
Raman spectroscopyfirst-principles calculationshigh pressurephase transitiontungsten ditellurideMore Related Videos
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