Department of Physics, Beijing Normal University, Beijing 100875, China.
Beijing Computational Science Research Center, Beijing 100193, China.
Sci Rep. 2017 Feb 10;7:42262. doi: 10.1038/srep42262.
We reveal an edge spin triplet p-wave superconducting pairing correlation in slightly doped zigzag graphene nanoribbons. By employing a method that combines random-phase approximation, the finite-temperature determinant quantum Monte Carlo approach, and the ground-state constrained-path quantum Monte Carlo method, it is shown that such a spin-triplet pairing is mediated by the ferromagnetic fluctuations caused by the flat band at the edge. The spin susceptibility and effective pairing interactions at the edge strongly increase as the on-site Coulomb interaction increases, indicating the importance of electron-electron correlations. It is also found that the doping-dependent ground-state p-wave pairing correlation bears some similarity to the famous superconducting dome in the phase diagram of a high-temperature superconductor, while the spin correlation at the edge is weakened as the system is doped away from half filling.
我们揭示了在轻度掺杂的锯齿形石墨烯纳米带中存在边缘自旋三重态 p 波超导配对相关。通过采用一种结合随机相位近似、有限温度行列式量子蒙特卡罗方法和基态约束路径量子蒙特卡罗方法的方法，表明这种自旋三重态配对是由边缘的平带引起的铁磁涨落介导的。随着局域库仑相互作用的增加，边缘处的自旋磁化率和有效配对相互作用大大增加，这表明电子-电子相关性的重要性。还发现，掺杂依赖的基态 p 波配对相关与高温超导体相图中的著名超导穹顶具有一定的相似性，而当系统掺杂远离半满时，边缘处的自旋相关性会减弱。
