Pseudogap formation due to charge-transfer transition and Kondo effect

Abstract

We investigate the doping evolution of the electronic state of the three-band t-J-U model considering the normal state of the hole-doped high-Tc superconducting cuprate. In our model, when some number of holes are doped into the undoped state, the d electron exhibits the charge-transfer-type Mott-Hubbard transition along with a chemical potential jump. A reduced charge-transfer gap is formed from the p band and the coherent component of the d band, and it shrinks due to charge fluctuations as more holes are doped as in the pseudogap phenomenon. This trend is reinforced as the d-p band hybridization is increased, and a Fermi liquid state is retrieved as in the Kondo effect. These suggest that the pseudogap in the hole-doped cuprate emerges due to the charge-transfer transition and the Kondo effect.