Tunable superconductivity in electron- and hole-doped Bernal bilayer graphene

التفاصيل البيبلوغرافية
العنوان: Tunable superconductivity in electron- and hole-doped Bernal bilayer graphene
المؤلفون: Li, Chushan, Xu, Fan, Li, Bohao, Li, Jiayi, Li, Guoan, Watanabe, Kenji, Taniguchi, Takashi, Tong, Bingbing, Shen, Jie, Lu, Li, Jia, Jinfeng, Wu, Fengcheng, Liu, Xiaoxue, Li, Tingxin
سنة النشر: 2024
المجموعة: Condensed Matter
مصطلحات موضوعية: Condensed Matter - Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics
الوصف: Graphene-based, high quality two-dimensional electronic systems have emerged as a highly tunable platform for studying superconductivity. Specifically, superconductivity has been observed in both electron-doped and hole-doped twisted graphene moire systems, whereas in crystalline graphene systems, superconductivity has so far only been observed in hole-doped rhombohedral trilayer and hole-doped Bernal bilayer graphene (BBG). Recently, enhanced superconductivity has been demonstrated in BBG due to the proximity with a monolayer WSe2. Here, we report the observation of superconductivity and a series of flavor-symmetry-breaking phases in both electron- and hole-doped BBG/WSe2 device by electrostatic doping. The strength of the observed superconductivity is tunable by applied vertical electric fields. The maximum Berezinskii-Kosterlitz-Thouless (BKT) transition temperature for the electron- and hole-doped superconductivity is about 210 mK and 400 mK, respectively. Superconductivities emerge only when applied electric fields drive BBG electron or hole wavefunctions toward the WSe2 layer, underscoring the importance of the WSe2 layer in the observed superconductivity. We find the hole-doped superconductivity violates the Pauli paramagnetic limit, consistent with an Ising-like superconductor. In contrast, the electron-doped superconductivity obeys the Pauli limit, even though the proximity induced Ising spin-orbit coupling is also notable in the conduction band. Our findings highlight the rich physics associated with the conduction band in BBG, paving the way for further studies into the superconducting mechanisms of crystalline graphene and the development of novel superconductor devices based on BBG.
نوع الوثيقة: Working Paper
DOI: 10.1038/s41586-024-07584-w
URL الوصول: http://arxiv.org/abs/2405.04479
رقم الانضمام: edsarx.2405.04479
قاعدة البيانات: arXiv
الوصف
DOI:10.1038/s41586-024-07584-w