A New Superconducting 3R-WS2 Phase at High Pressure
Wenting Zhang1, Yuqiang Fang2, Zihan Zhang1
1State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
The Journal of Physical Chemistry Letters
|March 26, 2021
Summary
High pressure transforms 2M-WS₂ superconductivity into a semiconductor phase. Subsequent high pressure induces metallization and superconductivity in the 3R-WS₂ phase, a first for transition metal dichalcogenides.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Superconductivity
Background:
- High-pressure studies are crucial for discovering novel material properties and superconducting phases.
- Transition metal dichalcogenides (TMDs), like WS₂, exhibit unique electronic behaviors.
- 2M-WS₂ shows record ambient pressure superconductivity (8.8 K) among TMDs.
Purpose of the Study:
- Investigate the effect of high pressure on the superconducting properties of 2M-WS₂.
- Explore pressure-induced phase transitions and their impact on superconductivity.
- Determine the conditions for superconductivity in different WS₂ phases.
Main Methods:
- Electrical resistance measurements under high pressure.
- Synchrotron X-ray diffraction for structural analysis.
- Theoretical calculations to understand electronic structure changes.
Main Results:
- Superconductivity in 2M-WS₂ was suppressed above 15 GPa, coinciding with a phase transition to semiconducting 3R-WS₂.
- Metallization and superconductivity (Tc ≈ 2.5 K) were observed in 3R-WS₂ at 48.8 GPa.
- This marks the first experimental observation of superconductivity in the 3R-WS₂ phase of TMDs.
Conclusions:
- Pressure-induced changes in interlayer coupling significantly alter the density of states near the Fermi surface.
- These changes explain the loss of superconductivity in 2M-WS₂ and its reappearance in 3R-WS₂.
- The findings offer new insights into controlling superconductivity in layered materials through pressure engineering.
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