Anisotropy and Strong-Coupling Effects on the Collective Mode Spectrum of Chiral Superconductors: Application to Sr${}_2$RuO${}_4$

Abstract

Recent theories of Sr${}_2$RuO${}_4$ based on the interplay of strong interactions, spin-orbit coupling and multi-band anisotropy predict chiral or helical ground states with strong anisotropy of the pairing states, with deep minima in the excitation gap, as well as strong phase anisotropy for the chiral ground state. We develop time-dependent mean field theory to calculate the Bosonic spectrum for the class of 2D chiral superconductors spanning ${}^3$He-A to chiral superconductors with strong anisotropy. Chiral superconductors support a pair of massive Bosonic excitations of the time-reversed pairs labeled by their parity under charge conjugation. These modes are degenerate for 2D ${}^3$He-A. Crystal field anisotropy lifts the degeneracy. Strong anisotropy also leads to low-lying Fermions, and thus to channels for the decay of the Bosonic modes. Selection rules and phase space considerations lead to large asymmetries in the lifetimes and hybridization of the Bosonic modes with the continuum of un-bound Fermion pairs. We also highlight results for the excitation of the Bosonic modes by microwave radiation that provide clear signatures of the Bosonic modes of an anisotropic chiral ground state.

11 pages with 8 figures. Presented as an invited talk as SCES14, Grenoble, France, July 2014

References in corpus (11)

• Strong spin-orbit coupling effects on the Fermi surface of Sr2RuO4 and Sr2RhO4
• Hidden quasi one-dimensional superconductivity in Sr${}_2$RuO${}_4$
• Is Sr2RuO4 a Chiral P-Wave Superconductor?
• Inelastic neutron scattering study of magnetic excitations in Sr${}_2$RuO${}_4$
• Pairing symmetry and dominant band in Sr2RuO4
• Theory of superconductivity in a three-orbital model of Sr${}_2$RuO${}_4$
• Crystalline order in superfluid 3He films
• Higgs bosons in particle physics and in condensed matter
• Charge and spin collective modes in a quasi-1D model of Sr2RuO4
• Thermodynamic Potential for Superfluid 3He in Aerogel
• Collective Modes and Nonlinear Acoustics in Superfluid 3He-B

Cited by in corpus (14)

• Spectroscopic signatures of time-reversal symmetry breaking superconductivity
• Possible three-dimensional nematic odd-parity superconductivity in Sr${}_2$RuO${}_4$
• Leggett modes and multi-band superconductivity in Sr2RuO4
• Chiral Higgs Mode in Nematic Superconductors
• Cooper-Pair Spin Current in a Strontium Ruthenate Heterostructure
• Surface Cooper pair spin waves in triplet superconductors
• Bound collective modes in nonuniform superconductors
• Topological Superfluids
• On the Excitations of a Balian-Werthamer Superconductor
• Universal collective modes in 2 dimensional chiral superfluids
• Anomalous acoustoelectric effect induced by clapping modes in chiral superconductors
• Bosonic Surface States and Acoustic Spectroscopy of Confined Superfluid ${}^3$He-B
• Kibble-Zurek Dynamics & Statistics of Topological Defects in Chiral Superfluid ${}^3$He Films
• Superconducting on-chip spectrometer for mesoscopic quantum systems