Influence of Coulomb interaction on the anisotropic Dirac cone in graphene
Influence of Coulomb interaction on the anisotropic Dirac cone in graphene
复制标题
库仑相互作用对石墨烯中各向异性狄拉克锥的影响
DOI：
10.1103/physrevb.89.195404
复制
发表时间：
2013-09
影响因子：
3.7
通讯作者：
Guo-Zhu Liu
中科院分区：
文献类型：
--
作者：
Jing-Rong Wang;Guo-Zhu Liu
各向异性狄拉克锥可以出现在许多相关的电子系统中，如铜超导体和变形石墨烯。利用重整化群方法和1/N展开（N为狄拉克费米子的味数），研究了远距离库仑相互作用对各向异性石墨烯物理性质的影响。我们的显式计算表明，各向异性费米子速度单调地流向清洁石墨烯中最低能量极限的各向同性固定点。然后，我们将随机化学势、随机规范势和随机质量三种紊乱纳入其中，并表明库仑相互作用和紊乱的相互作用可以导致丰富和不寻常的行为。在强库仑相互作用和随机化学势的存在下，费米子速度在低能量下被驱动消失，系统被证明是一个奇异的各向异性绝缘体。在库仑相互作用和其他两种类型的紊乱存在下，系统比清洁情况下更快地流向各向同性低能量不动点，并表现出非费米液体行为。我们还研究了库仑相互作用的非摄动效应，重点研究了速度各向异性对动态间隙的影响。研究发现，随着费米子速度的减小（增加），动力学间隙增强（抑制），但随着速度各向异性的增加而抑制。
Anisotropic Dirac cones can appear in a number of correlated electron systems, such as cuprate superconductors and deformed graphene. We study the influence of long-range Coulomb interaction on the physical properties of an anisotropic graphene by using the renormalization group method and 1/N expansion, where N is the flavor of Dirac fermions. Our explicit calculations reveal that the anisotropic fermion velocities flow monotonously to an isotropic fixed point in the lowest energy limit in clean graphene. We then incorporate three sorts of disorders, including random chemical potential, random gauge potential, and random mass, and show that the interplay of Coulomb interaction and disorders can lead to rich and unusual behaviors. In the presence of strong Coulomb interaction and a random chemical potential, the fermion velocities are driven to vanish at low energies and the system turns out to be an exotic anisotropic insulator. In the presence of Coulomb interaction and other two types of disorders, the system flows to an isotropic low-energy fixed point more rapidly than the clean case, and exhibits non-Fermi liquid behaviors. We also investigate the nonperturbative effects of Coulomb interaction, focusing on how the dynamical gap is affected by the velocity anisotropy. It is found that the dynamical gap is enhanced (suppressed) as the fermion velocities decrease (increase), but is suppressed as the velocity anisotropy increases.
DOI：
10.1142/9789814343336
发表时间：
1993
期刊：
--
影响因子：
--
作者：
V. A. Miransky
通讯作者：
V. A. Miransky