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Title: Microscopic out-of-equilibrium analysis of the zero-bias conductance peak in a one-dimensional topological superconductor

Abstract

Recently there has been a lot of excitement generated by the possibility of realizing and detecting Majorana fermions within the arena of condensed matter physics and its potential implication for topological quantum computing. In the pursuit of identifying and understanding the signatures of Majorana fermions in realistic systems, we go beyond the low-energy effective-model descriptions of Majorana bound states to derive non-equilibrium transport properties of a topological superconducting wire in the presence of arbitrarily large applied voltages. By virtue of a microscopic calculation we are able to model the tunnel coupling between the superconducting wire and the metallic leads realistically, study the role of high-energy non-topological excitations, predict how the behavior compares for an increasing number of odd versus even number of sites, and study the evolution across the topological quantum phase transition. We consider the Kitaev model as well as its specific realization in terms of a semiconductor-superconductor hybrid structures. Our results have concrete implications for the experimental search and study of Majorana fermions. Here I provide a brief selected summary of the talk presented during the fourth conference on Nuclei and Mesoscopic Physics (NMP14) which took place during May 5th-9th, 2014 at the National Superconducting Cyclotron Laboratory (NSCL),more » on the campus of Michigan State University, in East Lansing, Michigan.« less

Authors:
 [1]
  1. Department of Physics, University of Cincinnati, OH 45221-0011 (United States)
Publication Date:
OSTI Identifier:
22307984
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1619; Journal Issue: 1; Conference: 4. conference on nuclei and mesoscopic physics 2014, East Lansing, MI (United States), 5-9 May 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOUND STATE; COMPARATIVE EVALUATIONS; COUPLING; ELECTRIC POTENTIAL; EQUILIBRIUM; EXCITATION; FERMIONS; ONE-DIMENSIONAL CALCULATIONS; PHASE TRANSFORMATIONS; QUANTUM COMPUTERS; SEMICONDUCTOR MATERIALS; SUPERCONDUCTING WIRES; SUPERCONDUCTORS; TOPOLOGY

Citation Formats

Shah, Nayana. Microscopic out-of-equilibrium analysis of the zero-bias conductance peak in a one-dimensional topological superconductor. United States: N. p., 2014. Web. doi:10.1063/1.4899231.
Shah, Nayana. Microscopic out-of-equilibrium analysis of the zero-bias conductance peak in a one-dimensional topological superconductor. United States. doi:10.1063/1.4899231.
Shah, Nayana. Wed . "Microscopic out-of-equilibrium analysis of the zero-bias conductance peak in a one-dimensional topological superconductor". United States. doi:10.1063/1.4899231.
@article{osti_22307984,
title = {Microscopic out-of-equilibrium analysis of the zero-bias conductance peak in a one-dimensional topological superconductor},
author = {Shah, Nayana},
abstractNote = {Recently there has been a lot of excitement generated by the possibility of realizing and detecting Majorana fermions within the arena of condensed matter physics and its potential implication for topological quantum computing. In the pursuit of identifying and understanding the signatures of Majorana fermions in realistic systems, we go beyond the low-energy effective-model descriptions of Majorana bound states to derive non-equilibrium transport properties of a topological superconducting wire in the presence of arbitrarily large applied voltages. By virtue of a microscopic calculation we are able to model the tunnel coupling between the superconducting wire and the metallic leads realistically, study the role of high-energy non-topological excitations, predict how the behavior compares for an increasing number of odd versus even number of sites, and study the evolution across the topological quantum phase transition. We consider the Kitaev model as well as its specific realization in terms of a semiconductor-superconductor hybrid structures. Our results have concrete implications for the experimental search and study of Majorana fermions. Here I provide a brief selected summary of the talk presented during the fourth conference on Nuclei and Mesoscopic Physics (NMP14) which took place during May 5th-9th, 2014 at the National Superconducting Cyclotron Laboratory (NSCL), on the campus of Michigan State University, in East Lansing, Michigan.},
doi = {10.1063/1.4899231},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1619,
place = {United States},
year = {Wed Oct 15 00:00:00 EDT 2014},
month = {Wed Oct 15 00:00:00 EDT 2014}
}
  • Zero-bias anomalies in topological nanowires have recently captured significant attention, as they are possible signatures of Majorana modes. Yet there are many other possible origins of zero-bias peaks in nanowires—for example, weak localization, Andreev bound states, or the Kondo effect. Here, we discuss observations of differential-conductance peaks at zero-bias voltage in non-superconducting electronic transport through a 3D topological insulator (Bi 1.33Sb 0.67)Se 3 nanowire. The zero-bias conductance peaks show logarithmic temperature dependence and often linear splitting with magnetic fields, both of which are signatures of the Kondo effect in quantum dots. As a result, we characterize the zero-bias peaks andmore » discuss their origin.« less
  • We have examined the zero-bias conductance peak that is often found in high-temperature-superconductor tunnel-junction spectra. We have also measured the Bi-Sr-Ca-Cu-O thin-film energy gap. The zero-bias conductance peak can be explained in terms of quasiparticle tunneling, phase diffusion, and a supercurrent. The implications of this model are discussed.
  • We report the observation of a pronounced high zero-bias conductance peak (ZBCP) in the conductance spectra of (110)-oriented YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} epitaxial thin-film surfaces by low-temperature scanning tunneling microscopy/spectroscopy at 4.2 K. On films with very low surface roughness, both the superconducting gap structure and the ZBCP could be clearly observed in the spectra and neither depended on the measurement position or on the distance between the tunneling tip and the sample surface. This result is in agreement with the recent theoretical prediction of the formation of bound states on surfaces of d-wave superconductors that lead to a ZBCPmore » with a maximum for (110)-oriented surfaces. {copyright} {ital 1997} {ital The American Physical Society}« less
  • We consistently observe a magnetic-field-dependent conductance peak at zero-bias voltage in a wide range of superconductor/noble-metal junctions fabricated from oxide superconductors (YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O) that have been reported to exhibit d-wave pairing behavior; however, no measurable peak appears in similar junctions made from an s-wave oxide superconductor (Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4}). Explanations of this correlation are considered in terms of the Appelbaum-Anderson model for magnetic interface scattering and the midgap-state model for d-wave interface states. {copyright} {ital 1997} {ital The American Physical Society}