Charge carrier correlation in the electron-dopedt−Jmodel

Abstract

We study the t-tЈ-tЉ-J model with parameters chosen to model an electron-doped high-temperature superconductor. The model with one, two, and four charge carriers is solved on a 32-site lattice using exact diagonalization. Our results demonstrate that at doping levels up to x = 0.125 the model possesses robust antiferromagnetic correlation. When doped with one charge carrier, the ground state has momenta ͑± ,0͒ and ͑0, ± ͒. On further doping, charge carriers are unbound and the momentum distribution function can be constructed from that of the single-carrier ground state. The Fermi surface resembles that of small pockets at single-charge-carrier ground-state momenta, which is the expected result in a lightly doped antiferromagnet. This feature persists upon doping up to the largest doping level we achieved. We therefore do not observe the Fermi surface changing shape at doping levels up to 0.125.

Nonresonant Raman response of inhomogeneous structures in the electron-dopedt‐t′Hubbard model

“…19 The t-tЈ Hubbard model has also been studied with UHF in the past 20,21 where it was pointed out that tЈ favors homogeneous solutions in the electrondoped case in contrast to the hole-doped case. This was claimed to be due to the fact that tЈ does not frustrate the antiferromagnetism in the electron-doped case as was also proven with other techniques as exact diagonalization in the electron-doped t-tЈ-J model 22,23 and in quantum Monte Carlo calculations of the t-tЈ Hubbard model. 7,24 Metallic antiferromagnetism has been found in experiments.…”