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Tuning topological superconductivity in phase-controlled Josephson junctions with Rashba and Dresselhaus spin-orbit coupling

Scharf, Benedikt and Pientka, Falko and Ren, Hechen and Yacoby, Amir and Hankiewicz, Ewelina M. (2019) Tuning topological superconductivity in phase-controlled Josephson junctions with Rashba and Dresselhaus spin-orbit coupling. Physical Review B, 99 (21). Art. No. 214503. ISSN 2469-9950. http://resolver.caltech.edu/CaltechAUTHORS:20190612-140920221

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Abstract

Recently, topological superconductors based on Josephson junctions in two-dimensional electron gases with strong Rashba spin-orbit coupling have been proposed as attractive alternatives to wire-based setups. Here, we elucidate how phase-controlled Josephson junctions based on quantum wells with [001] growth direction and an arbitrary combination of Rashba and Dresselhaus spin-orbit coupling can also host Majorana bound states for a wide range of parameters as long as the magnetic field is oriented appropriately. Hence, Majorana bound states based on Josephson junctions can appear in a wide class of two-dimensional electron gases. We study the effect of spin-orbit coupling, the Zeeman energies, and the superconducting phase difference to create a full topological phase diagram and find the optimal stability region to observe Majorana bound states in narrow junctions. Surprisingly, for equal Rashba and Dresselhaus spin-orbit coupling, well localized Majorana bound states can appear only for phase differences ϕ ≠ π as the topological gap protecting the Majorana bound states vanishes at ϕ = π . Our results show that the ratio between Rashba and Dresselhaus spin-orbit coupling or the choice of the in-plane crystallographic axis along which the superconducting phase bias is applied offer additional tunable knobs to test Majorana bound states in these systems. Finally, we discuss signatures of Majorana bound states that could be probed experimentally by tunneling conductance measurements at the edge of the junction.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/physrevb.99.214503DOIArticle
https://arxiv.org/abs/1904.08981arXivDiscussion Paper
Additional Information:© 2019 American Physical Society. Received 18 April 2019; revised manuscript received 30 May 2019; published 12 June 2019. We thank Bertrand Halperin, Michael Kosowsky, Andrew Saydjari, Julian-Benedikt Mayer, and Florian Goth for valuable discussions. B.S. and E.M.H. acknowledge financial support by the German Research Foundation (DFG) through SFB 1170 “ToCoTronics” and through the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter, ct.qmat (EXC 2147, Project No. 39085490) and by the ENB Graduate School on Topological Insulators. F.P. acknowledges financial support by the STC Center for Integrated Quantum Materials under NSF Grant No. DMR-1231319. H.R. acknowledges funding provided by the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center, NSF Grant No. PHY-1733907. A.Y. acknowledges funding by the NSF Grant No. DMR-1708688, the STC Center for Integrated Quantum Materials under NSF Grant No. DMR-1231319, the NSF GRFP under Grant No. DGE1144152, and the US Army Research Office under Grant No. W911NF-18-1-0316.
Group:IQIM, Institute for Quantum Information and Matter
Funders:
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)SFB 1170
Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter39085490
ENB Graduate School on Topological InsulatorsUNSPECIFIED
NSFDMR-1231319
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
NSFPHY-1733907
NSFDMR-1708688
NSFDMR-1231319
NSF Graduate Research FellowshipDGE-1144152
Army Research Office (ARO)W911NF-18-1-0316
Record Number:CaltechAUTHORS:20190612-140920221
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20190612-140920221
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96339
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:12 Jun 2019 21:16
Last Modified:12 Jun 2019 21:16

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