Evolution of topological superconductivity by orbital-selective confinement in oxide nanowires

C. A. Perroni, V. Cataudella, M. Salluzzo, M. Cuoco, and R. Citro
Phys. Rev. B 100, 094526 – Published 20 September 2019

Abstract

We determine the optimal conditions to achieve topological superconducting phases having spin-singlet pairing for a planar nanowire with a finite lateral width in the presence of an in-plane external magnetic field. We employ a microscopic description that is based on a three-band electronic model including both the atomic spin-orbit coupling and the inversion asymmetric potential at the interface between oxide band-gap insulators. We consider amplitudes of the pairing gap, spin-orbit interactions, and electronic parameters that are directly applicable to nanowires of LaAlO3SrTiO3. The lateral confinement introduces a splitting of the d orbitals that alters the orbital energy hierarchy and significantly affects the electron filling dependence of the topological phase diagram. Due to the orbital directionality of the t2g states, we find that in the regime of strong confinement the onset of topological phases is pinned at electron filling where the quasiflat heavy bands start to get populated. The increase of the nanowire thickness leads to a changeover from a sparse-to-dense distribution of topologically nontrivial domains which occurs at the crossover associated with the orbital population inversion. These findings are corroborated by a detailed analysis of the most favorable topological superconducting phases in the electron doping–magnetic field plane highlighting the role of orbital-selective confinement.

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  • Received 4 June 2019
  • Revised 10 September 2019

DOI:https://doi.org/10.1103/PhysRevB.100.094526

©2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

C. A. Perroni and V. Cataudella

  • CNR-SPIN and Physics Department “Ettore Pancini,” Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Napoli, Italy

M. Salluzzo

  • CNR-SPIN, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Napoli, Italy

M. Cuoco and R. Citro

  • CNR-SPIN and Physics Department “E. R. Caianiello,” Università degli Studi di Salerno, Via Giovanni Paolo II, 132, I-84084 Fisciano (Sa), Italy

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Issue

Vol. 100, Iss. 9 — 1 September 2019

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