arXiv subjects

Arpita Koley

Publications and source records attributed to Arpita Koley.

2 recordsLinked to original sources

arXiv2026

Transport signatures of topological commensurate off-diagonal Aubry-Andr\'e-Harper chain

We study the interplay between quantum transport and topology in a one-dimensional off-diagonal commensurate Aubry-Andr\'e-Harper (AAH) chain. The model, formulated within AAH framework, effectively represents a one-dimensional lattice with two competing commensurate modulations, supporting two distinct types of topological edge modes: zero-energy states in the central gapless region and quantum Hall (QH) edge states bridging the gapped bulk bands. These edge modes govern the transport behavior and give rise to sharp variations in transmission across the corresponding gap-closing transitions. A pronounced even-odd effect further emerges, where chains with an odd number of sites exhibit nearly perfect zero-energy transmission at the Dirac points, independent of system-lead coupling, system size, or modulation strength; a robust signature of ballistic transport. To capture the influence of environmental decoherence, we also incorporate B\"uttiker dephasing probes, which enable a phenomenological description of inelastic scattering and reveal how dephasing modifies, and in some regimes enhances, coherent transport.

cond-mat.mes-hall↗

arXiv2021

Magnetic response of interacting electrons in a spatially non-uniform disordered multi-channel system: Exact and mean-field results

In this work we explore magnetic response of interacting electrons in a spatially non-uniform disordered system, where impurities are introduced in one sector of the geometry keeping the other one free. The interaction among the electrons are taken in the well known Hubbard form which leads to several anomalous features in energy spectra and flux driven circular current, depending on the concentration of up and down spin electrons. For smaller systems with less number of electrons we present exact results which always give a clear picture to understand the basic mechanisms, while for large systems having higher number of electrons mean-field results are given. The effect of disorder is very interesting. Beyond a critical disorder, completely contrasting signature is obtained compared to uniform disordered systems, and the phenomenon becomes more promising when the Hubbard interaction is included. Along with these features, we find unusual half flux-quantum periodic current at some typical cases and a suitable explanation of it is provided. Our detailed analysis may be utilized to study magnetic response of interacting electrons in other similar kind of non-uniform disordered systems.

cond-mat.mes-hall↗