论文标题
菱形三层石墨烯中超导性的功能重归其化组研究
Functional Renormalization Group Study of Superconductivity in Rhombohedral Trilayer Graphene
论文作者
论文摘要
我们采用一种功能性重归其化组方法来确定在菱形三层石墨烯中观察到的超导相的配对机理和对称性。该系统中的超导性发生在载体密度和位移场的状态下，具有弱扭曲的环形费米海。我们发现，排斥性的库仑相互作用可以通过利用与费米海洋环的有限宽度相关的动量空间结构来诱导费米表面上的电子配对。山谷 - 交换相互作用在RG流动下增强并发展非平凡的动量空间结构，可以提高自旋平线和自旋三型配对之间的脱落性。我们发现，领先的配对不稳定性是$ d $ - 挥发性的和旋转的单曲，并且理论相图与载体密度与位移字段与实验定性一致。
We employ a functional renormalization group approach to ascertain the pairing mechanism and symmetry of the superconducting phase observed in rhombohedral trilayer graphene. Superconductivity in this system occurs in a regime of carrier density and displacement field with a weakly distorted annular Fermi sea. We find that repulsive Coulomb interactions can induce electron pairing on the Fermi surface by taking advantage of momentum-space structure associated with the finite width of the Fermi sea annulus. The degeneracy between spin-singlet and spin-triplet pairing is lifted by valley-exchange interactions that strengthen under the RG flow and develop nontrivial momentum-space structure. We find that the leading pairing instability is $d$-wave-like and spin-singlet, and that the theoretical phase diagram versus carrier density and displacement field agrees qualitatively with experiment.
