TopologicalD+p-wave superconductivity in Rashba systems

Abstract

We show two-dimensional "strong" topological superconductivity in d-wave superconductors (SCs). Although the topological invariant of the bulk wave function cannot be defined in d x 2 −y 2 -wave and dxy-wave SCs because of nodal excitations, the bulk energy spectrum of d-wave SCs on a substrate is fully gapped in a magnetic field. Then the superconducting state is specified by a nontrivial Chern number, and hence topologically nontrivial properties are robust against disorders and interactions. We discuss high-temperature topological superconductivity in cuprate SCs recently fabricated on a substrate. Furthermore, we show that the three-dimensional noncentrosymmetric d-wave SC is a Weyl SC hosting topologically protected Weyl nodes. Noncentrosymmetric heavy-fermion SCs, such as CeRhSi3 and CeIrSi3, are candidates for Weyl SCs.

Parity-mixing superconducting phase in the Rashba-Hubbard model and its topological properties from dynamical mean-field theory

“…Note that g k = −g −k , and thus the Rashba coupling breaks inversion symmetry, but does not break time-reversal invariance; the Zeeman field h does, however. This is the arXiv:1807.02489v1 [cond-mat.supr-con] 6 Jul 2018 model adopted by Yoshida and Yanase [11]. In the presence of superconductivity, the mean-field, Bogoliubov-de Gennes Hamiltonian requires a doubling of the degrees of freedom in order to be expressed in the usual form:…”

“…On the other hand, a greater variety of triplet states is possible. We will probe the state studied by Yoshida and Yanase [11], in which the dvector takes the form d k = ∆ p (sin k y , sin k x , 0). This triplet gap function is chosen because it belongs to the same irreducible representation of the point group C 4v of the noninteracting Hamiltonian as the d-wave gap function, and thus can mix with it.…”

“…An important role of the Zeeman magnetic field is to break time-reversal symmetry in the system, which leads to nontrivial topological properties [7,11]. Fig.…”

Non‐Centrosymmetric Superconductors on Honeycomb Lattice

“…The purpose of this paper is to explore all possible topologically non‐trivial non‐centrosymmetric superconducting states in graphene‐based materials by combining all the phenomena mentioned above, including the effects of intrinsic (KM) and the Rashba SO couplings, the mixture of d + id spin singlet and triplet p + ip ‐wave pairings in the presence of both KM and the Rashba SO couplings. A recent related study on the simplified model without KM interaction in cuprates has shown non‐trivial topological properties . However, there is still lack of a comprehensive analysis of the more general and generic model systems for NCS on honeycomb lattice.…”

d + id and d wave topological superconductors and new mechanisms for bulk boundary correspondence

“…13 Some other recent researches concerning topological superconductor include. 14,15 But, so far, it has been largely overlooked for the 2D TR breaking C 2 = −1 (class C in the Altland-Zirnbauer(AZ) classification 16,17 ) topological superconductors and for the 3D TR invariant class CI topological superconductors with T 2 = 1 and C 2 = −1. A few previous researches, by constructing theoretical models for simplest cases, include.…”