Localization, transport, and edge states in a two-strand ladder network in an aperiodically staggered magnetic field

Article

关键词: WAVE-FUNCTIONS;    PERTURBATION-THEORY;    CHARGE-TRANSPORT;    HALL;    CONDUCTANCE;    SYSTEMS;    TRANSITION;    BREATHERS;    ELECTRONS;    FERMIONS;   

DOI  :  10.1103/PhysRevB.102.134401

来源: SCIE

【 摘 要 】

We investigate the spectral and transport properties of a two-arm tight-binding ladder perturbed by an external magnetic field following an Aubry-Andre-Harper profile. The varying magnetic flux trapped in consecutive ladder cells simulates an axial twist that enables us, in principle, to probe a wide variety of systems ranging from a ribbon Hofstadter geometry to helical DNA chains. We perform an in-depth numerical analysis, using a direct diagonalization of the lattice Hamiltonian to study the electronic spectra and transport properties of the model. We show that such a geometry creates a self-similar multifractal pattern in the energy landscape. The spectral properties are analyzed using the local density of states and a Green's function formalism is employed to obtain the two-terminal transmission probability. With the standard multifractal analysis and the evaluation of inverse participation ratio we show that the system hosts both critical and extended phase for a slowly varying aperiodic sequence of flux indicating a possible mobility edge. Finally, we report signatures of topological edge modes that are found to be robust against a correlated perturbation given to the nearest-neighbor hopping integrals. Our results can be of importance in experiments involving ladderlike quantum networks, realized with cold atoms in an optical trap setup.

【 授权许可】

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