講演題目: Band-center metal-insulator transition in bond-disordered graphene
講師: Soumya Bera 氏 (インド工科大学ボンベイ校)
日時: 2023年10月10日(火) 16:30〜17:30
場所: 工学部 オープンホール
要旨:
We study the transport properties of a tight-binding model of non-interacting fermions with random hopping on the honeycomb lattice. At the particle-hole symmetric chemical potential, the absence of diagonal disorder (random onsite potentials) places the system in the well-studied chiral orthogonal universality class of disordered fermion problems, which are known to exhibit both a critical metallic phase and a dimerization-induced localized phase. Here, our focus is the behavior of the two-terminal conductance and the Lyapunov spectrum in quasi-1D geometry near the dimerization-driven transition from the metallic to the localized phase. For a staggered dimerization pattern on the square and honeycomb lattices, we find that the renormalized localization lengthξ/M (M denotes the width of the sample) and the typical conductance display scaling behavior controlled by a crossover length-scale that diverges with exponent ν≈1.05(5) as the critical point is approached.
世話人 小布施 秀明
(hideaki.obuse@eng.hokudai.ac.jp)
北海道大学大学院工学研究院応用物理学部門