arXiv subjects

Nirnoy Basak

Publications and source records attributed to Nirnoy Basak.

4 recordsLinked to original sources

arXiv2026

Universal magnetotunnel conductance at a Weyl semimetal-layered Chern insulator junction

We investigate electronic transport across a junction between a Weyl semimetal (WSM) and a layered Chern insulator (LCI) in the presence of a magnetic field perpendicular to the interface. The topological mismatch between the gapless Weyl semimetal and the momentum-resolved chiral edge modes of the layered Chern insulator leads to interface Fermi-arc states with a qualitatively distinct connectivity: unlike WSM-WSM junctions, the interface Fermi arcs are forced to reconnect through the Brillouin-zone boundary rather than terminating at the projections of the Weyl nodes. We analyze the spectrum and compute the magneto tunnel conductance mediated by the interface-localized states. We find that the conductance increases linearly with magnetic field at low fields and saturates beyond a critical field to a constant value that is independent of microscopic details such as interface coupling, arc geometry, and lattice-scale parameters. This universal saturation reflects a transport mechanism governed by the topological charge pumping associated with the Chern layers, rather than magnetic breakdown between Fermi arcs. We further show that, under specific conditions, a junction between two distinct Weyl semimetals can exhibit a similar saturation behavior, thereby clarifying the topological origin of the observed universality.

cond-mat.mes-hall↗

arXiv2026

Topologically switchable transport in a bundled cable of wires

Advances in the next generation of mesoscopic electronics require an understanding of topological phases in inhomogeneous media and the principles that govern them. Motivated by the nature of motifs available in printable conducting inks, we introduce and study quantum transport in a minimal model that describes a bundle of one-dimensional metallic wires that are randomly interconnected by semiconducting chains. Each of these interconnects is represented by a Su-Schrieffer-Heeger chain, which can reside in either a trivial or a topological phase. Using a tight-binding approach, we show that such a system can transit from an insulating phase to a robust metallic phase as the interconnects undergo a transition from a trivial to a topological phase. In the latter, despite the random interconnectedness, the metal evades Anderson localization and exhibits a ballistic conductance that scales linearly with the number of wires. We show that this behavior originates from hopping renormalization in the wire network. The zero-energy modes of the topological interconnects act as effective random dimers, giving rise to an energy-dependent localization length that diverges as $\sim 1/E^2$. Our work establishes that random networks provide a yet-unexplored platform to host intriguing phases of topological quantum matter.

cond-mat.mes-hall↗

arXiv2024

Magneto tunnel conductance across twisted Weyl semimetal junctions

We investigate magnetotransport across an interface between two Weyl semimetals (finite in both directions) whose Weyl nodes project onto two different surfaces which are twisted with respect to each other before being coupled. This gives rise to a novel contribution to the conductance through the junction purely through Fermi arc states, even in the absence of a magnetic field perpendicular to the junction. When the perpendicular magnetic field is included, we find that for a mesoscopic or smaller samples, the transverse Fermi arc states have a significant contribution to the conductance for experimentally relevant fields, and need to be taken into account along with the conductance through the bulk chiral Landau levels.

cond-mat.mes-hall↗

arXiv2023

Thermoelectric properties of inversion symmetry broken Weyl semimetal-Weyl superconductor hybrid junctions

We theoretically investigate the thermoelectric properties (electronic contribution) of a hybrid structure comprising of an inversion symmetry broken Weyl semimetal (WSM) and intrinsic Weyl superconductor (WSC) with $s$-wave pairing, employing the Blonder-Tinkham-Klapwijk formulation for non-interacting electrons. Our study unfolds interesting features for various relevant physical quantities such as the thermal conductance, the thermoelectric coefficient and the corresponding figure of merit. We also explore the effects of an interfacial insulating (I) barrier (WSM-I-WSC set-up) on the thermoelectric response in the thin barrier limit. Further, we compute the ratio of the thermal to the electrical conductance in different temperature regimes and find that the Wiedemann-Franz law is violated for small temperatures (below critical temperature $T_{c}$) near the Weyl points while it saturates to the Lorentz number, away from the Weyl points, at all temperatures irrespective of the barrier strength. We compare and contrast this behaviour with other Dirac material heterostructures and provide a detailed analysis of the thermal transport. Our study can facilitate the fabrication of mesoscopic thermoelectric devices based on WSMs.

cond-mat.mes-hall↗