Interaction effects in topological superconducting wires supporting Majorana fermions
Among the broad spectrum of systems predicted to exhibit topological superconductivity and Majorana fermions, one-dimensional wires with strong spin-orbit coupling provide one of the most promising experimental candidates. Here we investigate the fate of the topological superconducting phase in such wires when repulsive interactions are present. Using a combination of density matrix renormalization group, bosonization, and Hartree–Fock techniques, we demonstrate that while interactions degrade the bulk gap—consistent with recent results of Gangadharaiah et al.—they also greatly expand the parameter range over which the topological phase arises. In particular, we show that with interactions this phase can be accessed over a broader chemical potential window, thereby leading to greater immunity against disorder-induced chemical potential fluctuations in the wire. We also suggest that in certain wires strong interactions may allow Majorana fermions to be generated without requiring a magnetic field.
Additional Information© 2011 American Physical Society. (Received 4 May 2011; published 14 July 2011) It is a pleasure to acknowledge helpful discussions with Lukasz Fidkowski, Roman Lutchyn, Roderich Moessner, Lesik Motrunich and Felix von Oppen. We would especially like to thank Steve White for not only contributing helpful discussions but also the DMRG code and methods without which this paper would not be possible. We gratefully acknowledge support from the National Science Foundation through Grant Nos. DMR-0907500 (E.M.S.), DMR-1055522 (J.A.), DMR-0808842 (O.A.S.), and DMR-0529399 (M.P.A.F.). This research was supported in part by the National Science Foundation under Grant No. NSF PHY05-51164. O.A.S. also acknowledges the KITP, where part of this work was carried out, for hospitality.
Published - PhysRevB.84.014503.pdf
Submitted - 1104.5493.pdf