Possible singlet and triplet superconductivity on honeycomb lattice
Possible singlet and triplet superconductivity on honeycomb lattice
复制标题
蜂窝晶格上可能的单线态和三线态超导
DOI：
10.1209/0295-5075/115/27008
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发表时间：
2016
期刊：
影响因子：
1.8
通讯作者：
Li Jian-Xin
中科院分区：
文献类型：
--
作者：
Xiao Long-Yun;Yu Shun-Li;Wang Wei;Yao Zi-Jian;Li Jian-Xin
利用扩展的Hubbard模型和随机相近似方法，研究了蜂窝晶格上可能存在的由自旋和电荷涨落介导的超导配对对称性。从2%到20%掺杂水平，当只考虑在位库仑相互作用U时，自旋单线态波是主要的超导配对对称性，能隙函数是最近邻和次近邻配对的混合体。当两个子晶格之间的能级偏移量超过一个临界值时，最有利的配对是主要由次近邻配对组成的自旋三重态f波。我们发现，次近邻库仑相互作用V也有利于自旋-三重态f波配对。
We study the possible superconducting pairing symmetry mediated by spin and charge fluctuations on the honeycomb lattice using the extended Hubbard model and the random-phase-approximation method. From 2% to 20% doping levels, a spin-singlet -wave is shown to be the leading superconducting pairing symmetry when only the on-site Coulomb interaction U is considered, with the gap function being a mixture of the nearest-neighbor and next-nearest-neighbor pairings. When the offset of the energy level between the two sublattices exceeds a critical value, the most favorable pairing is a spin-triplet f-wave which is mainly composed of the next-nearest-neighbor pairing. We show that the next-nearest-neighbor Coulomb interaction V is also in favor of the spin-triplet f-wave pairing.