Park H, Haule K, Kotliar G
Department of Physics, Rutgers University, Piscataway, New Jersey 08854, USA.
Phys Rev Lett. 2008 Oct 31;101(18):186403. doi: 10.1103/PhysRevLett.101.186403. Epub 2008 Oct 30.
We address the nature of the Mott transition in the Hubbard model at half-filling using cluster dynamical mean field theory (DMFT). We compare cluster-DMFT results with those of single-site DMFT. We show that inclusion of the short-range correlations on top of the on-site correlations does not change the order of the transition between the paramagnetic metal and the paramagnetic Mott insulator, which remains first order. However, the short range correlations reduce substantially the critical U and modify the shape of the transition lines. Moreover, they lead to very different physical properties of the metallic and insulating phases near the transition point. Approaching the transition from the metallic side, we find an anomalous metallic state with very low coherence scale. The insulating state is characterized by the narrow Mott gap with pronounced peaks at the gap edge.
我们使用团簇动力学平均场理论（DMFT）研究了哈伯德模型在半填充时莫特转变的本质。我们将团簇DMFT结果与单格点DMFT结果进行了比较。我们表明，在位点关联之上包含短程关联并不会改变顺磁金属和顺磁莫特绝缘体之间转变的阶数，该转变仍然是一级的。然而，短程关联显著降低了临界U并改变了转变线的形状。此外，它们导致了转变点附近金属相和绝缘相非常不同的物理性质。从金属侧接近转变时，我们发现了一个具有非常低相干长度的反常金属态。绝缘态的特征是具有狭窄的莫特能隙，在能隙边缘有明显的峰值。
