The Vortex Core Excitation Spectrum in Gapped Topological d-wave Superconductors

Abstract

There are indications that some high T c unconventional superconductors have a "complex" dwave order parameter d x 2 −y 2 + iαd xy (with an admixture of s-wave) leading to nonzero energy gap ∆. Since the coherence length is short and the Fermi energy is relatively small the quasiclassical approach is inapplicable and the more complicated Bogoliubov-deGennes equations should be used to investigate the excitation spectrum of such a material in a magneric field. It turns out that equations for the chiral d-wave superconductor, α = ±1 simplify considerably and is the basis for any superconductor of that type with a sufficiently large gap. The spectrum of core excitations of the Abrikosov vortex in an anisotropic 3D sample exhibits several features. Unlike in conventional and gapless superconductors the core has a single excitation mode of order ∆ for each value of momentum along the field. This has a large impact on thermal transport and vortex dynamics.

Duality in topological superconductors and topological ferromagnetic insulators in a honeycomb lattice

“…[23][24][25] More recently, possible solutions of spin-singlet topological superconductors via spontaneously TRS breaking are proposed. [26][27][28][29] In particular, the ground state for electrons on the honeycomb lattice in the large Hubbard U limit are shown to be of chiral d-wave pairing symmetry, d x 2 −y 2 + id xy (d + id), 30 which indicates that the honeycomb lattice might be a good platform to host chiral Majorana modes.…”

Vortex bound states of charge and magnetic fluctuations induced topological superconductors in heterostructures

“…For non-chiral d-wave superconductor d x 2 −y 2 the existence of exteneded 29 and localized core states 30,31 have been discucussed. The analoge of discrete Caroli-de Gennes-Matricon core states 32 for spin-rotatinally symetric chiral d-wave superconductors has been studied 29,33 , but no zero modes are reported. The heterostrucure of topological insulator Bi 2 Se 3 film on a nodal d-wave superconductor Bi 2 Sr 2 CaCu 2 O 8+δ has been experimentally studied recently where a rather large induced and isoptropic superconducting gap was reported 34 .…”