Nematicity and competing orders in superconducting magic-angle graphene

Strongly interacting electrons in solid-state systems often display multiple broken symmetries in the ground state. The interplay between different order parameters can give rise to a rich phase diagram. We report on the identification of intertwined phases with broken rotational symmetry in magic-a...

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Veröffentlicht in:Science (American Association for the Advancement of Science) 2021-04, Vol.372 (6539), p.264-271
Hauptverfasser: Cao, Yuan, Rodan-Legrain, Daniel, Park, Jeong Min, Yuan, Noah F Q, Watanabe, Kenji, Taniguchi, Takashi, Fernandes, Rafael M, Fu, Liang, Jarillo-Herrero, Pablo
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Sprache:eng
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Zusammenfassung:Strongly interacting electrons in solid-state systems often display multiple broken symmetries in the ground state. The interplay between different order parameters can give rise to a rich phase diagram. We report on the identification of intertwined phases with broken rotational symmetry in magic-angle twisted bilayer graphene (TBG). Using transverse resistance measurements, we find a strongly anisotropic phase located in a "wedge" above the underdoped region of the superconducting dome. Upon its crossing with the superconducting dome, a reduction of the critical temperature is observed. Furthermore, the superconducting state exhibits an anisotropic response to a direction-dependent in-plane magnetic field, revealing nematic ordering across the entire superconducting dome. These results indicate that nematic fluctuations might play an important role in the low-temperature phases of magic-angle TBG.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.abc2836