Capone Massimo, Fabrizio Michele, Castellani Claudio, Tosatti Erio
Enrico Fermi Center, Rome, Italy.
Phys Rev Lett. 2004 Jul 23;93(4):047001. doi: 10.1103/PhysRevLett.93.047001. Epub 2004 Jul 22.
Near a Mott transition, strong electron correlations may enhance Cooper pairing. This is demonstrated in the dynamical mean field theory solution of a twofold-orbital degenerate Hubbard model with an inverted on-site Hund rule exchange, favoring local spin-singlet configurations. Close to the Mott insulator (which here is a local version of a valence bond insulator) a pseudogap non-Fermi-liquid metal, a superconductor, and a normal metal appear, in striking similarity with the physics of cuprates. The strongly correlated s-wave superconducting state has a larger Drude weight than the corresponding normal state. The role of the impurity Kondo problem is underscored.
在莫特转变附近，强电子关联可能增强库珀对。这在具有倒转在位洪德规则交换的双轨道简并哈伯德模型的动态平均场理论解中得到了证明，该交换有利于局域自旋单重态构型。接近莫特绝缘体（这里是价键绝缘体的局域版本）时，会出现赝能隙非费米液体金属、超导体和正常金属，这与铜酸盐的物理性质惊人地相似。强关联的s波超导态比相应的正常态具有更大的德鲁德权重。杂质近藤问题的作用得到了强调。
