Topological Superconductivity without Proximity Effect

Abstract

Majorana Fermions, strange particles that are their own antiparticles, were predicted in 1937 and have been sought after ever since. In condensed matter they are predicted to exist as vortex core or edge excitations in certain exotic superconductors. These are topological superconductors whose order parameter phase winds non-trivially in momentum space. In recent years, a new and promising route for realizing topological superconductors has opened due to advances in the field of topological insulators. Current proposals are based on semiconductor heterostructures, where spin-orbit coupled bands are split by a band gap or Zeeman field and superconductivity is induced by proximity to a conventional superconductor. Topological superconductivity is obtained in the interface layer. The proposed heterostructures typically include two or three layers of different materials. In the current work we propose a device based on materials with inherent spin-orbit coupling and an intrinsic tendency for superconductivity, eliminating the need for a separate superconducting layer. We study a lattice model that includes spin-orbit coupling as well as on-site and nearest neighbor interaction. Within this model we show that topological superconductivity is possible in certain regions of parameter space. These regions of non-trivial topology can be understood as a nodeless superconductor with d-wave symmetry which, due to the spin-orbit coupling, acquires an extra phase twist of $2\pi$.

5 Pages, 3 Figures

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Cited by in corpus (11)

• Topological superconductors: a review
• Anderson Topological Superconductor
• Entanglement Spectrum as a Probe for the Topology of a Spin-Orbit Coupled Superconductor
• Strong Coupling Expansion of the Extended Hubbard Model with Spin-Orbit Coupling
• Reentrant topological transitions with Majorana end states in 1D superconductors by lattice modulation
• Quasiparticle Interference Patterns in a Topological Superconductor
• Zeeman field induced non-trivial topology in a spin-orbit coupled superconductor
• Strain-induced superconductivity in Sr2IrO4
• Incommensurate spin density wave as a signature of spin-orbit coupling
• Analytic Expression for the Entanglement Entropy of a 2D Topological Superconductor
• Charge glass in an extended dimer Hubbard model