Gao Jiming, Wang Jiaxiang
State Key Laboratory of Precision Spectroscopy and Department of Physics, East China Normal University, Shanghai 200062, People's Republic of China. College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, People's Republic of China.
J Phys Condens Matter. 2009 Dec 2;21(48):485702. doi: 10.1088/0953-8984/21/48/485702. Epub 2009 Oct 30.
In this paper, we have investigated the metal-insulator transition (MIT) in a two-dimensional half-filled extended Hubbard model on an isotropic triangular lattice with a real space block renormalization group technique. It has been found that the MIT can be driven nontrivially by either the on-site interaction U or the nearest-neighbor one V, but with different critical exponents. Depending upon the values of V, the system could have one, two or three MIT critical points. Moreover, for the metallic regime, we have also studied the competition effect from the spin density wave and charge density wave phases by using a mean-field theory based upon Hartree-Fock approximations. Finally, the single-site entanglement is also calculated and its first derivative with respect to U shows a jump along the critical line of the MIT.
在本文中，我们使用实空间块重整化群技术研究了各向同性三角形晶格上二维半填充扩展哈伯德模型中的金属 - 绝缘体转变（MIT）。研究发现，MIT可以由在位相互作用U或最近邻相互作用V非平凡地驱动，但具有不同的临界指数。根据V的值，系统可能有一个、两个或三个MIT临界点。此外，对于金属态，我们还通过基于哈特里 - 福克近似的平均场理论研究了自旋密度波和电荷密度波相的竞争效应。最后，还计算了单格点纠缠，并且其关于U的一阶导数在MIT的临界线上显示出一个跳跃。
