Density of States in Two-Dimensional Square Lattices Around Half Filling with Strong Impurities  

作　　者：GUYu YANGYong-Hong WANGYong-Gang ZHANGQun 

机构地区：[1]DepartmentofPhysics,SoutheastUniversity,Nanjing210096,China [2]DepartmentofPhysics,SoutheastUniversity,Nanjing210096,China／／NationalLaboratoryofSolidStateMicrostructures,NanjingUniversity,Nanjing210008,China

出　　处：《Communications in Theoretical Physics》2005年第4期743-748,共6页理论物理通讯（英文版）

基　　金：国家自然科学基金，江苏省自然科学基金，教育部新世纪高校优秀人才计划

摘　　要：We calculate the lowest-order quantum-interference correction to the density of states (DOS) of weakly-disordered two-dimensional (2D) tight-binding square lattices around half filling. The impurities are assumed to be randomly distributed on small fractions of the sites, and have a-strong potential yielding a unitary-limit scattering. In addition to the usual diffusive modes in the retarded-advanced channel, there appear diffusive pi modes in the retarded-retarded (or advanced-advanced) channel due to the existence of particle-hole symmetry. It is found that the pi-mode diffuson gives rise to a logarithmic suppression to the DOS near the band center, which prevails over the positive correction contributed by pi-mode cooperon. As a result, the DOS is subject to a negative total correction. This result is qualitatively different from the divergent behavior of the DOS at the band center predicted previously for disordered 2D two-sublattice models with the particle-hole symmetry.

关 键 词：WEAK-LOCALIZATION density of states two-dimensional lattice 

分 类 号：O431.2[机械工程—光学工程]