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Decoupling superconductivity and correlated insulators in twisted bilayer graphene

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 نشر من قبل Yu Saito
 تاريخ النشر 2019
  مجال البحث فيزياء
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When bilayer graphene is rotationally faulted to an angle $thetaapprox 1.1^circ$, theory predicts the formation of a flat electronic band and correlated insulating, superconducting, and ferromagnetic states have all been observed at partial band filling. The proximity of superconductivity to correlated insulators has suggested a close relationship between these states, reminiscent of the cuprates where superconductivity arises by doping a Mott insulator. Here, we show that superconductivity can appear without correlated insulating states. While both superconductivity and correlated insulating behavior are strongest near the flat band condition, superconductivity survives to larger detuning of the angle. Our observations are consistent with a competing phases picture, in which insulators and superconductivity arise from disparate mechanisms.



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