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Nematicity and competing orders in superconducting magic-angle graphene
Yuan Cao1, Daniel Rodan-Legrain2, Jeong Min Park2
1Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. caoyuan@mit.edu pjarillo@mit.edu.
Science (New York, N.Y.)
|April 16, 2021
Summary
Researchers discovered intertwined phases with broken rotational symmetry in magic-angle twisted bilayer graphene (TBG). This nematic ordering influences superconductivity, suggesting nematic fluctuations are key to TBG
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Strongly interacting electrons in solids lead to complex ground states with broken symmetries.
- The interplay of multiple order parameters creates rich phase diagrams in materials.
Purpose of the Study:
- To identify intertwined phases and broken symmetries in magic-angle twisted bilayer graphene (TBG).
- To investigate the relationship between these phases and superconductivity in TBG.
Main Methods:
- Utilized transverse resistance measurements.
- Applied direction-dependent in-plane magnetic fields.
Main Results:
- Identified a strongly anisotropic phase in TBG, located above the underdoped superconducting region.
- Observed a reduction in critical temperature where this anisotropic phase intersects the superconducting dome.
- Revealed nematic ordering across the entire superconducting dome via anisotropic magnetic field response.
Conclusions:
- Nematic ordering is present throughout the superconducting dome in magic-angle TBG.
- Nematic fluctuations are likely crucial for understanding the low-temperature phases of magic-angle TBG.
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