Unconventional Pairings and Radial Line Nodes in Inversion Symmetry Broken Superconductors

Abstract

Noncentrosymmetric superconductors (NCSs) with broken inversion symmetry can have spin-dependent order parameters (OPs) with mixed parity which can also have nodes in the pair potential as well as the energy spectra. These nodes are distinct features that are not present in conventional superconductors. They appear as points or lines in the momentum space where the latter can have angular or radial geometries dictated by the dimensionality, the lattice structure and the pairing interaction. In this work we study the nodes in time reversal symmetry (TRS) preserving NCSs at the OP, the pair potential, and the energy spectrum levels. Nodes are examined by using spin independent pairing interactions respecting the rotational $C_{\infty v}$ symmetry in the presence of spin-orbit coupling (SOC). The pairing symmetries and the nodal topology are affected by the relative strength of the pairing channels which is studied for the mixed singlet-triplet, pure singlet, and pure triplet. Complementary to the angular line nodes widely present in the literature, the $C_{\infty v}$ symmetry here allows radial line nodes (RLNs) due to the nonlinear momentum dependence in the OPs. The topology of the RLNs in the mixed case shows a distinctly different characterization than the half-spin quantum vortex at the Dirac point. We apply this NCS physics to the inversion symmetry broken exciton condensates (ECs) in double quantum wells where the point and the RLNs can be found. On the other hand, for a pure triplet condensate, two fully gapped and topologically distinct regimes exist, separated by a QSHI-like zero energy superconducting state with even number of Majorana modes. We also remark on how the point and the RLNs can be manipulated, enabling an external control on the topology.tions.

[8 pages, 6 figures, 1 table (main)]

References in corpus (15)

• Topological Field Theory of Time-Reversal Invariant Insulators
• Topological Phases of Noncentrosymmetric Superconductors: Edge States, Majorana Fermions, and the Non-Abelian Statistics
• Topology of crystalline insulators and superconductors
• Classification of reflection symmetry protected topological semimetals and nodal superconductors
• Spin Triplet Superconducting State due to Broken Inversion Symmetry in Li_2Pt_3B
• Topological spin-current in non-centrosymmetric superconductors
• Two-dimensional time-reversal-invariant topological superconductivity in a doped quantum spin Hall insulator
• Nodal Structure of Superconductors with Time-Reversal Invariance and Z2 Topological Number
• Electric and Magnetic Tuning Between the Trivial and Topological Phases in InAs/GaSb Double Quantum Wells
• Odd-parity superconductivity from phonon-mediated pairing: Application to Cu${}_x$Bi${}_2$Se${}_3$
• Multigap superconductivity in sesquicarbides La${}_2$C${}_3$ and Y${}_2$C${}_3$
• Finite-Volume Electromagnetic Corrections to the Masses of Mesons, Baryons and Nuclei
• Spin-singlet superconductivity with a full gap in locally non-centrosymmetric SrPtAs
• Anisotropic superconductivity in the noncentrosymmetric BiPd
• Probing the superconducting ground state of the noncentrosymmetric superconductors CaTSi3 (T = Ir, Pt) using muon-spin relaxation and rotation

Cited by in corpus (1)

• Weakly Anisotropic Noncentrosymmetric Superconductors with Radial Line Nodes and Thermodynamical Anomalies