Metallic phase in the two-dimensional ionic Hubbard model
Metallic phase in the two-dimensional ionic Hubbard model
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DOI：
10.1103/physrevb.76.085112
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发表时间：
2007-05
影响因子：
3.7
通讯作者：
K. Bouadim;N. Paris;F. Hébert;G. Batrouni;R. Scalettar
中科院分区：
文献类型：
--
作者：
K. Bouadim;N. Paris;F. Hébert;G. Batrouni;R. Scalettar
用行列式量子蒙特卡罗(DQMC)方法研究了二维正方形晶格中离子Hubbard模型的相结构。在半填充时，当相互作用强度或交错电势占主导地位时，我们分别找到了Mott和带状绝缘体。当这两个能级相同时，我们发现一个金属区域。电荷和磁结构因素只在Mott区存在反铁磁性，尽管外加的密度调制在相图中随处可见。除了半填充外，还发现了其他绝缘相。动能关联不能给出明确的键序相存在的信号。
We investigate the phases of the ionic Hubbard model in a two-dimensional square lattice using determinant quantum Monte Carlo (DQMC). At half-filling, when the interaction strength or the staggered potential dominate we find Mott and band insulators, respectively. When these two energies are of the same order we find a metallic region. Charge and magnetic structure factors demonstrate the presence of antiferromagnetism only in the Mott region, although the externally imposed density modulation is present everywhere in the phase diagram. Away from half-filling, other insulating phases are found. Kinetic energy correlations do not give clear signals for the existence of a bond-ordered phase.