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

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

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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.

flat-band systemdynamicscorrelated disorder

李骐、刘军丰、刘克、胡自翔、李舟

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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

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National Natural science Foundation of ChinaKey Research and Development Program of Guangdong ProvinceScience and Technology Planning Project of Guangdong ProvinceGuangzhou Basic and Applied Basic Research ProjectChinese Academy of Sciences ZChinese Academy of Sciences ZZJ projectJSPSJSPSHZWTECHNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaFundamental Research Funds for the Central Universities

619881022019B0909170072019B0909090112023A04J0018ElZ1D10200E2Z2D102002021QN02X159PE14052P1602711974064121471022020CDJQY-Z003

2024

10.1088/1674-1056/ad5534

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
年,卷(期)：2024.33(9)