Approaching a topological phase transition in Majorana nanowires
Abstract
Recent experiments have produced mounting evidence of Majorana zero modes in nanowire-superconductor hybrids. Signatures of an expected topological phase transition accompanying the onset of these modes nevertheless remain elusive. We investigate a fundamental question concerning this issue: Do well-formed Majorana modes necessarily entail a sharp phase transition in these setups? Assuming reasonable parameters, we argue that finite-size effects can dramatically smooth this putative transition into a crossover, even in systems large enough to support well-localized Majorana modes. We propose overcoming such finite-size effects by examining the behavior of low-lying excited states through tunneling spectroscopy. In particular, the excited-state energies exhibit characteristic field and density dependence, and scaling with system size, that expose an approaching topological phase transition. We suggest several experiments for extracting the predicted behavior. As a useful byproduct, the protocols also allow one to measure the wire's spin-orbit coupling directly in its superconducting environment.
Additional Information
© 2016 American Physical Society. (Received 3 February 2016; revised manuscript received 6 May 2016; published 8 June 2016) We are indebted to M. Deng, K. Flensberg, L. Glazman, M. Hell, and C. Marcus for helpful discussions on this work, and especially thank M. Deng and C. Marcus for sharing unpublished results. We also gratefully acknowledge support from the NSERC PGSD program (D.A.); the National Science Foundation through Grant No. DMR-1341822 (J.A.); the Alfred P. Sloan Foundation (J.A.); the Caltech Institute for Quantum Information and Matter, an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation through Grant No. GBMF1250; and the Walter Burke Institute for Theoretical Physics at Caltech. Part of this work was performed at the Aspen Center for Physics, which is supported by National Science Foundation Grant No. PHY-1066293 (R.V.M.).Attached Files
Published - PhysRevB.93.245404.pdf
Submitted - 1601.07908v1.pdf
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Additional details
- Eprint ID
- 66840
- Resolver ID
- CaltechAUTHORS:20160510-085332659
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- NSF
- DMR-1341822
- Alfred P. Sloan Foundation
- Institute for Quantum Information and Matter (IQIM)
- Gordon and Betty Moore Foundation
- GBMF1250
- Walter Burke Institute for Theoretical Physics, Caltech
- NSF
- PHY-1066293
- NSF Physics Frontiers Center
- Created
-
2016-05-10Created from EPrint's datestamp field
- Updated
-
2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Walter Burke Institute for Theoretical Physics, Institute for Quantum Information and Matter