大槻 東巳

<p>前回Lifshitz tailの原因となる局在電子をワイル半金属において存在することを数値的に確認し報告した。引き続きワイル半金属をモデルに今回は定量評価として局在電子の系のサイズ依存性について検証した。局在電子数とサイズの関係から現実的なサイズでLifshitz tailが半金属-金属相転移に影響を及ぼすのか議論する。</p>

The Anderson transition is a disorder driven quantum phase transition between metallic and insulating phases. In contrast to the common belief that two dimensional (2D) systems are always insulating and that the Anderson transition does not occur in 2D, in certain universality classes 2D systems can be metallic. We review the recent development of the theory of the Anderson transition in 2D. There are ten universality classes: three Wigner-Dyson classes, three chiral universality classes, and four Bogoliubov-de Gennes classes. We report results for critical exponents and distributions of conductance for the symplectic universality class. We emphasize that, on the one hand, the existence of a topological insulating phase does not alter the value of the critical exponent, while on the other, it strongly affects the form of the conductance distribution at the transition.