Capone M, Sangiovanni G, Castellani C, Di Castro C, Grilli M
Enrico Fermi Center, Rome, Italy.
Phys Rev Lett. 2004 Mar 12;92(10):106401. doi: 10.1103/PhysRevLett.92.106401. Epub 2004 Mar 10.
The density-driven Mott transition is studied by means of dynamical mean-field theory in the Hubbard-Holstein model, where the Hubbard term leading to the Mott transition is supplemented by an electron-phonon (e-ph) term. We show that an intermediate e-ph coupling leads to a first-order transition at T=0, which is accompanied by a phase separation between a metal and an insulator. The compressibility in the metallic phase is substantially enhanced. At quite larger values of the coupling, a polaronic phase emerges coexisting with a nonpolaronic metal.
在哈伯德 - 霍尔斯坦模型中，通过动态平均场理论研究了密度驱动的莫特转变，其中导致莫特转变的哈伯德项由一个电子 - 声子（e - ph）项补充。我们表明，中等强度的电子 - 声子耦合在T = 0时导致一级转变，同时伴随着金属和绝缘体之间的相分离。金属相中的压缩性显著增强。在耦合强度相当大时，出现了一个极化子相并与非极化子金属共存。
