Topological insulator constrictions -- Dirac particles in a magneto-chiral box

Fuente: arXiv
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Auteurs principaux: Barth, Michael, Fürst, Maximilian, Kozlovsky, Raphael, Richter, Klaus, Gorini, Cosimo
Format: Preprint
Publié: 2025
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author Barth, Michael
Fürst, Maximilian
Kozlovsky, Raphael
Richter, Klaus
Gorini, Cosimo
author_facet Barth, Michael
Fürst, Maximilian
Kozlovsky, Raphael
Richter, Klaus
Gorini, Cosimo
contents We study magneto-transport through topological insulator nanowires shaped in the form of a constriction, as can be obtained by etching techniques. The magnetic field is coaxial, potentially turning the nanowire into a magneto-chiral junction. We show in a detailed analytical and numerical study that two main transport regimes emerge, depending on the central narrow region being short or long as compared to the magnetic length at the junction entrance and exit. In both cases the central region hosts Dirac-particle-in-a-box states due to magnetic confinement, whose conductance properties are strongly influenced by Landau levels at the ends of the constriction. Notably, in the low-energy regime only chiral states with a specific handedness can transport charge across the junction. Based on these properties and general symmetry considerations we argue that the shaped nanowire should exhibit strong magneto-chiral non-reciprocal transport beyond linear response. We employ a numerical tight-binding implementation of an effective 2D model on a non-homogeneous grid, capable of simulating samples of realistic sizes, and test its soundness against full simulations for scaled-down 3D topological insulator wires.
format Preprint
id arxiv_https___arxiv_org_abs_2501_17687
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Topological insulator constrictions -- Dirac particles in a magneto-chiral box
Barth, Michael
Fürst, Maximilian
Kozlovsky, Raphael
Richter, Klaus
Gorini, Cosimo
Mesoscale and Nanoscale Physics
We study magneto-transport through topological insulator nanowires shaped in the form of a constriction, as can be obtained by etching techniques. The magnetic field is coaxial, potentially turning the nanowire into a magneto-chiral junction. We show in a detailed analytical and numerical study that two main transport regimes emerge, depending on the central narrow region being short or long as compared to the magnetic length at the junction entrance and exit. In both cases the central region hosts Dirac-particle-in-a-box states due to magnetic confinement, whose conductance properties are strongly influenced by Landau levels at the ends of the constriction. Notably, in the low-energy regime only chiral states with a specific handedness can transport charge across the junction. Based on these properties and general symmetry considerations we argue that the shaped nanowire should exhibit strong magneto-chiral non-reciprocal transport beyond linear response. We employ a numerical tight-binding implementation of an effective 2D model on a non-homogeneous grid, capable of simulating samples of realistic sizes, and test its soundness against full simulations for scaled-down 3D topological insulator wires.
title Topological insulator constrictions -- Dirac particles in a magneto-chiral box
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2501.17687