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

李骐 ¹刘军丰 ²刘克 ¹胡自翔 ³李舟⁴

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作者信息

1. 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
2. School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,China
3. Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics,Chongqing University,Chongqing 401331,China
4. 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;University of Chinese Academy of Sciences,Beijing 100039,China
折叠

Abstract

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 α-T3 model,and find that the initial flat-band wave packet preserves its localization when α=0,regardless of disorder and intersections.However,when α≠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 Г point(k=0)in the Brillouin zone.

Key words

flat-band system/dynamics/correlated disorder

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基金项目

National Natural science Foundation of China(61988102)

Key Research and Development Program of Guangdong Province(2019B090917007)

Science and Technology Planning Project of Guangdong Province(2019B090909011)

Guangzhou Basic and Applied Basic Research Project(2023A04J0018)

Chinese Academy of Sciences Z(ElZ1D10200)

Chinese Academy of Sciences Z(E2Z2D10200)

ZJ project(2021QN02X159)

JSPS(PE14052)

JSPS(P16027)

HZWTECH()

National Natural Science Foundation of China(11974064)

National Natural Science Foundation of China(12147102)

Fundamental Research Funds for the Central Universities(2020CDJQY-Z003)

出版年

2024

中国物理B(英文版)

中国物理学会和中国科学院物理研究所

中国物理B(英文版)

CSTPCDEI

影响因子：0.995

ISSN：1674-1056

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