Superfluid states in α–T_(3) lattice  

作　　者：Yu-Rong Wu Yi-Cai Zhang 吴玉容;张义财(School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,China)

机构地区：[1]School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,China

出　　处：《Chinese Physics B》2021年第6期137-142,共6页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 11874127);the startup grant from Guangzhou University。

摘　　要：The superfluid states of attractive Hubbard model in α–T_(3) lattice are investigated. It is found that one usual needs three non-zero superfluid order parameters to describe the superfluid states due to three sublattices. When two hopping amplitudes are equal, the system has particle–hole symmetry. The flat band plays an important role in superfluid pairing near half filling. For example, when the filling factor falls into the flat band, the large density of states in the flat band favors superfluid pairing and the superfluid order parameters reach relatively large values. When the filling factor is in the gap between the flat band and upper band, the superfluid order parameters take small values due to the vanishing of density of states. The superfluid order parameters show nonmonotonic behaviors with the increase of filling factor. At last, we also investigate the edge states with open boundary conditions. It is shown that there exist some interesting edge states in the middle of quasi-particle bands.

关 键 词：superfluid states flat band α–T_(3)lattice particle–hole symmetry 

分 类 号：O469[理学—凝聚态物理]