Non-perturbative dynamics of flat-band systems with correlated disorder  

作　　者：Qi Li Junfeng Liu Ke Liu Zi-Xiang Hu Zhou Li 李骐;刘军丰;刘克;胡自翔;李舟(GBA Branch of Aerospace Information Research Institute,Chinese Academy of Sciences,Guangzhou 510535,China;Guangdong Provincial Key Laboratory of Terahertz Quantum Electromagnetics,Guangzhou 510700,China;School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,China;Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics,Chongqing University,Chongqing 401331,China;University of Chinese Academy of Sciences,Beijing 100039,China)

机构地区：[1]GBA Branch of Aerospace Information Research Institute,Chinese Academy of Sciences,Guangzhou 510535,China [2]Guangdong Provincial Key Laboratory of Terahertz Quantum Electromagnetics,Guangzhou 510700,China [3]School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,China [4]Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics,Chongqing University,Chongqing 401331,China [5]University of Chinese Academy of Sciences,Beijing 100039,China

出　　处：《Chinese Physics B》2024年第9期547-551,共5页中国物理B（英文版）

基　　金：the National Natural Sci-ence Foundation of China(Grant No.61988102);the Key Research and Development Program of Guangdong Province(Grant No.2019B090917007);the Science and Technology Planning Project of Guangdong Province(Grant No.2019B090909011);Q.L.acknowledges Guangzhou Basic and Applied Basic Research Project(Grant No.2023A04J0018);Z.L.acknowledges the support of fund-ing from Chinese Academy of Sciences E1Z1D10200 and E2Z2D10200;from ZJ project 2021QN02X159 and from JSPS(Grant Nos.PE14052 and P16027);We gratefully ac-knowledge HZWTECH for providing computation facilities.Z.-X.H.was supported by the National Natural Science Foun-dation of China(Grant Nos.11974064 and 12147102);the Fundamental Research Funds for the Central Universities(Grant No.2020CDJQY-Z003).

摘　　要：We develop a numerical method for the time evolution of Gaussian wave packets on flat-band lattices in the presence of correlated disorder.To achieve this,we introduce a method to generate random on-site energies with prescribed correlations.We verify this method with a one-dimensional(1D)cross-stitch model,and find good agreement with analytical results obtained from the disorder-dressed evolution equations.This allows us to reproduce previous findings,that disorder can mobilize 1D flat-band states which would otherwise remain localized.As explained by the corresponding disorder-dressed evolution equations,such mobilization requires an asymmetric disorder-induced coupling to dispersive bands,a condition that is generically not fulfilled when the flat-band is resonant with the dispersive bands at a Dirac point-like crossing.We exemplify this with the 1D Lieb lattice.While analytical expressions are not available for the two-dimensional(2D)system due to its complexity,we extend the numerical method to the 2D a–T3 model,and find that the initial flat-band wave packet preserves its localization when a=0,regardless of disorder and intersections.However,when a̸=0,the wave packet shifts in real space.We interpret this as a Berry phase controlled,disorder-induced wave-packet mobilization.In addition,we present density functional theory calculations of candidate materials,specifically Hg1−xCdxTe.The flat-band emerges near the G point(α=0)in the Brillouin zone.

关 键 词：flat-band system DYNAMICS correlated disorder 

分 类 号：O469[理学—凝聚态物理]