Effect of next-nearest-neighbor transfer on superconductivity and antiferromagnetism in two-dimensional t-J model

摘要

Effect of the diagonal transfer t' in a square lattice is studied, by applying a variational Monte Carlo method to the t-J model. Condensation energy of d-wave superconductivity increases (decreases) for hole-doped cases, t'/t < 0 (electron-doped cases, t'/t > 0), whereas antiferromagnetism (AF) is suppressed (enhanced) for t'/t < 0 (t'/t > 0). Furthermore, the AF state off half filling is intrinsically unstable and phase separates for t'/t less than or similar to 0, but stable even away from half filling for t'/t similar to 0.2. This result consistently explains recent experiments on the stability of the AF phases in cuprates. (c) 2005 Elsevier Ltd. All rights reserved.