Coherent Magneto-Conductance Oscillations in Amorphous Topological Insulator Nanowires

Fuente: arXiv
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Main Authors: Mal, Siddhant, Dresselhaus, Elizabeth J., Moore, Joel E.
Format: Preprint
Published: 2024
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author Mal, Siddhant
Dresselhaus, Elizabeth J.
Moore, Joel E.
author_facet Mal, Siddhant
Dresselhaus, Elizabeth J.
Moore, Joel E.
contents Recent experiments on amorphous materials have established the existence of surface states similar to those of crystalline three-dimensional topological insulators (TIs). Amorphous topological insulators are also independently of interest for thermo-electric and other properties. To develop an understanding of transport in these systems, we carry out quantum transport calculations for a tight-binding model of an amorphous nano-wire pierced by an axial magnetic flux, then compare the results to known features in the case of crystalline models with disorder. Our calculations complement previous studies in the crystalline case that studied the surface or used a Green's function method. We find that the periodicity of the conductance signal with varying magnetic flux is comparable to the crystalline case, with maxima occurring at odd multiples of magnetic flux quanta. However, the expected amplitude of the oscillation decreases with increasing amorphousness, as defined and described in the main text. We characterize this deviation from the crystalline case by taking ensemble averages of the conductance signatures for various wires with measurements simulated at finite temperatures. This striking transport phenomenon offers a metric to characterize amorphous TIs and stimulate further experiments on this class of materials.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09754
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Coherent Magneto-Conductance Oscillations in Amorphous Topological Insulator Nanowires
Mal, Siddhant
Dresselhaus, Elizabeth J.
Moore, Joel E.
Mesoscale and Nanoscale Physics
Disordered Systems and Neural Networks
Recent experiments on amorphous materials have established the existence of surface states similar to those of crystalline three-dimensional topological insulators (TIs). Amorphous topological insulators are also independently of interest for thermo-electric and other properties. To develop an understanding of transport in these systems, we carry out quantum transport calculations for a tight-binding model of an amorphous nano-wire pierced by an axial magnetic flux, then compare the results to known features in the case of crystalline models with disorder. Our calculations complement previous studies in the crystalline case that studied the surface or used a Green's function method. We find that the periodicity of the conductance signal with varying magnetic flux is comparable to the crystalline case, with maxima occurring at odd multiples of magnetic flux quanta. However, the expected amplitude of the oscillation decreases with increasing amorphousness, as defined and described in the main text. We characterize this deviation from the crystalline case by taking ensemble averages of the conductance signatures for various wires with measurements simulated at finite temperatures. This striking transport phenomenon offers a metric to characterize amorphous TIs and stimulate further experiments on this class of materials.
title Coherent Magneto-Conductance Oscillations in Amorphous Topological Insulator Nanowires
topic Mesoscale and Nanoscale Physics
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2411.09754