Partially separated Majorana modes in a disordered medium

Chuanchang Zeng, Girish Sharma, Sumanta Tewari, and Tudor Stanescu
Phys. Rev. B 105, 205122 – Published 19 May 2022

Abstract

Focusing on the implications of recent experiments on Majorana zero modes in semiconductor-superconductor (SM-SC) heterostructures, we critically examine the quantization of the zero-bias differential conductance as a possible unambiguous signature of Majorana physics in the presence of disorder. By numerically calculating the zero-bias conductance (ZBC) maps as function of Zeeman splitting and chemical potential for different disorder realizations, we find that the large topological region associated with the clean system, which is characterized by a quantized ZBC height 2e2/h, breaks up into progressively smaller “islands” as the disorder strength increases. For strong disorder we show that the presence of small islands with ZBC value (approximately) equal to 2e2/h, which we refer to as “quantized islands,” represents a unique signature of Majorana physics supporting partially separated Majorana modes (ps-MMs). Because of the small area/volume of these quantized islands in the parameter space, observing them in experiments may require sample selection and the systematic scanning of a large volume in the control parameter space. Upon decreasing disorder, the quantized islands increase in size and eventually coalesce into large topological regions. We conclude that the observation of quantized islands with ZBC value approximately equal to 2e2/h demonstrates unambiguously the presence of the key ingredients necessary for Majorana physics, provides an excellent diagnostic tool for evaluating the disorder strength, and, consequently, represents the next natural milestone in Majorana search.

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  • Received 13 September 2021
  • Revised 2 May 2022
  • Accepted 4 May 2022
  • Corrected 31 May 2022

DOI:https://doi.org/10.1103/PhysRevB.105.205122

©2022 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied PhysicsQuantum Information, Science & Technology

Corrections

31 May 2022

Correction: The previously published Figure 6 was a duplicate of Figure 7 and has been replaced with the correct figure.

Authors & Affiliations

Chuanchang Zeng1,2, Girish Sharma3, Sumanta Tewari4, and Tudor Stanescu5

  • 1Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
  • 2Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
  • 3School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175005 (H.P.), India
  • 4Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, USA
  • 5Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA

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Issue

Vol. 105, Iss. 20 — 15 May 2022

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