Mott transition in cuprate high-temperature superconductors

Abstract

In this study, we investigate the metal-insulator transition of charge transfer type in high-temperature cuprates. We first show that we must introduce a new band parameter in the three-band model to reproduce the Fermi surface of high-temperature cuprates such as BSCCO, YBCO and Hg1201. We present a new wave function of a Mott insulator based on the improved Gutzwiller function, and show that there is a transition from a metal to a charge-transfer insulator for such parameters by using the variational Monte Carlo method. This transition occurs when the level difference between d and p orbitals reaches a critical value . The energy gain , measured from the limit of large , is proportional to for : . We obtain using the realistic band parameters.