کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7987731 | 1515521 | 2018 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Singlet superconductivity enhanced by charge order in nested twisted bilayer graphene Fermi surfaces
ترجمه فارسی عنوان
ابررسانایی تک توسط سطوح فرمی به صورت سطوح گرافنی دو لایه پیچیده شده توسط دستور شارژ افزایش می یابد
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
دانش مواد (عمومی)
چکیده انگلیسی
Using the continuum model for low energy non-interacting electronic structure of moiré van der Waals heterostructures developed by Bistritzer and MacDonald [1], we study the competition between spin, charge, and superconducting order in twisted bilayer graphene. Surprisingly, we find that for a range of small angles inclusive of the so-called magic angle, this model features robust Fermi pockets that preclude any Mott insulating phase at weak coupling. However, a Fermi surface reconstruction at θâ¯â³â¯1.2° gives emergent van Hove singularities without any Fermi pockets. Using a hot-spot model for Fermi surface patches around these emergent saddle points, we develop a random-phase approximation from which we obtain a phase diagram very similar to that obtained recently by Isobe, Yuan, and Fu using the parquet renormalization group [2] but with additional insights. For example, our model shows strong nesting around time-reversal symmetric points at a moderate doping of â¼2â¯Ãâ¯1011â¯cmâ2 away from the van Hove singularity. When this nesting dominates, we predict that charge-order enhances singlet superconductivity, while spin-order suppresses superconductivity. Our theory also provides additional possibilities for the case of unnested Fermi surfaces.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Communications - Volume 282, October 2018, Pages 38-44
Journal: Solid State Communications - Volume 282, October 2018, Pages 38-44
نویسندگان
Evan Laksono, Jia Ning Leaw, Alexander Reaves, Manraaj Singh, Xinyun Wang, Shaffique Adam, Xingyu Gu,