2002/11/15 by Y. H. Yang, D. Y. Xing, Y. G. Wang +2
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Topological Materials and Phenomena #cond-mat.dis-nn #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.68.045113
21 pages, 4 figures
arxiv created 2002/11/15 · openalex publication_date 2003/07/29 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Based on the self-consistent T-matrix approximation, the quantum interference (QI) effects are studied with the diagrammatic technique in weakly disordered two-dimensional crystals with nearly half-filled bands. In addition to the usual 0-mode cooperon and diffuson, there exists \ensuremathπ-mode cooperon and diffuson in the unitary limit due to the particle-hole symmetry. The diffusive \ensuremathπ modes are gapped by the deviation from the exactly nested Fermi surface. The conductivity diagrams with the gapped \ensuremathπ-mode cooperon or diffuson are found to give rise to unconventional features of the QI effects. Besides inelastic scattering, thermal fluctuation is also shown to be an important dephasing mechanism in the QI processes related to the diffusive \ensuremathπ modes. In the proximity of the nesting case, a power-law antilocalization effect appears due to the \ensuremathπ-mode diffuson. For large deviation from the nested Fermi surface, this antilocalization effect is suppressed, and the conductivity remains to have the usual logarithmic weak-localization correction contributed by the 0-mode cooperon. As a result, the dc conductivity in the unitary limit becomes a nonmonotonic function of the temperature or the sample size, which is quite different from the prediction of the usual weak-localization theory.