Asia Pacific Center for Theoretical Physics, POSTECH, San 31 Hyoja-dong, Pohang 790-784, Korea.
J Phys Condens Matter. 2010 Mar 10;22(9):095602. doi: 10.1088/0953-8984/22/9/095602. Epub 2010 Feb 10.
We study electronic phase transitions in the half-filled ionic Hubbard model with an on-site Coulomb repulsion U and an ionic energy Δ by using the coherent potential approximation. For a fixed and finite Δ two transitions from the band insulator via a metallic state to a Mott insulator are found with increasing U. The values of the critical correlation-driven metal-insulator transitions U(c1)(Δ) and U(c2)(Δ) are estimated. Our results are in reasonable agreement with the ones obtained by single-site dynamical mean-field theory and determinant quantum Monte Carlo simulation.
我们使用相干势近似研究了具有局域库仑排斥 U 和离子能 Δ 的半满离子哈伯模型中的电子相变。对于固定的有限 Δ，随着 U 的增加，我们发现从带绝缘体通过金属态到莫特绝缘体的两个转变。我们估计了临界相关驱动的金属-绝缘体转变 U(c1)(Δ)和 U(c2)(Δ)的值。我们的结果与单点动力学平均场理论和行列式量子蒙特卡罗模拟得到的结果吻合良好。
