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Quantum criticality in twisted transition metal dichalcogenides
Augusto Ghiotto1, En-Min Shih1, Giancarlo S S G Pereira1
1Department of Physics, Columbia University, New York, NY, USA.
Nature
|September 16, 2021
Summary
Researchers studied metal-insulator transitions in twisted WSe2, observing strange metal behavior near the boundary. This work establishes a new platform for exploring quantum phase transitions in moiré heterostructures.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Metallic behavior defying conventional theories observed near quantum phase transitions.
- Moiré heterostructures exhibit gate-tuneable insulating phases driven by electronic correlations.
Purpose of the Study:
- Characterize metal-insulator transitions (MITs) in twisted WSe2.
- Investigate the nature of these transitions and the emergent electronic phases.
Main Methods:
- Transport measurements on twisted WSe2 moiré heterostructures.
- Analysis of resistivity as a function of carrier density and displacement field.
Main Results:
- Continuous MIT observed with tuning of density and displacement field.
- Strange metal behavior with Planckian dissipation at the MIT boundary.
- Recovery of Fermi liquid behavior, evolving into quantum critical fan and saturated regimes in the metallic phase.
- Evidence of strong quantum fluctuations in the insulating phase.
Conclusions:
- Twisted WSe2 serves as a novel platform for studying doping and bandwidth-controlled MITs.
- The observed phenomena provide insights into quantum criticality and non-Fermi liquid behavior.
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