On the Kinetic Energy Driven Superconductivity in the Two-Dimensional Hubbard Model

Takashi Yanagisawa, Kunihiko Yamaji, Mitake Miyazaki
2021 Condensed Matter  
We investigate the role of kinetic energy for the stability of superconducting state in the two-dimensional Hubbard model on the basis of an optimization variational Monte Carlo method. The wave function is optimized by multiplying by correlation operators of site off-diagonal type. This wave function is written in an exponential-type form given as ψλ=exp(−λK)ψG for the Gutzwiller wave function ψG and a kinetic operator K. The kinetic correlation operator exp(−λK) plays an important role in the
more » ... emergence of superconductivity in large-U region of the two-dimensional Hubbard model, where U is the on-site Coulomb repulsive interaction. We show that the superconducting condensation energy mainly originates from the kinetic energy in the strongly correlated region. This may indicate a possibility of high-temperature superconductivity due to the kinetic energy effect in correlated electron systems.
doi:10.3390/condmat6010012 fatcat:w4y4fskgxbcudei6t5g3a3h3wu