中国物理B ›› 2021, Vol. 30 ›› Issue (10): 107401-107401.doi: 10.1088/1674-1056/abec36
Huai-Shuang Zhu(祝怀霜) and Qiang Han(韩强)†
Huai-Shuang Zhu(祝怀霜) and Qiang Han(韩强)†
摘要: Understanding how electrons form pairs in the presence of strong electron correlations demands going beyond the BCS paradigm. We study a correlated superconducting model where the correlation effects are accounted for by a U term local in momentum space. The electron correlation is treated exactly while the electron pairing is treated approximately using the mean-field theory. The self-consistent equation for the pair potential is derived and solved. Somewhat contrary to expectation, a weak attractive U comparable to the pair potential can destroy the superconductivity, whereas for weak to intermediate repulsive U, the pair potential can be enhanced. The fidelity of the mean-field ground state is calculated to describe the strength of the elelectron correlation. We show that the pair potential is not equal to the single-electron superconducting gap for the strongly correlated superconductors, in contrast to the uncorrelated BCS limit.
中图分类号: (Theories and models of superconducting state)