Quantum to classical crossover under dephasing effects in a two-dimensional percolation model

• 作 者: Junjie Qi Haiwen Liu Chui-Zhen Chen Hua Jiang X.C.Xie
• 机 构: International Center for Quantum Materials and School of Physics, Peking University, Beijing 100871,
• 出 处: 中国科学:物理学 力学 天文学（英文版）
• 发表日期: 2020年2期
• 关键词: quantum percolation model dephasing effects metal-insulator crossover

Scaling theory predicts complete localization in d =2 in quantum systems belonging to the orthogonal class (i.e.,with timereversal symmetry and spin-rotation symmetry).The conductance g behaves as g ～ exp(-L/l) with system size L and localization length l in the strong disorder limit.However,classical systems can always have metallic states in which Ohm's law shows a constant g in d =2.We study a two-dimensional quantum percolation model by controlling dephasing effects.The numerical investigation of g aims at simulating a quantum-to-classical percolation evolution.An unexpected metallic phase,where g increases with L,generates immense interest before the system becomes completely classical.Furthermore,the analysis of the scaling plot of g indicates a metal-insulator crossover.