Collective Mode in a d_{x^2-y^2} + id_xy Superconductor

TL;DR

This paper predicts a new orbital magnetization mode in mixed-symmetry d+id' superconductors, which oscillates with a tunable frequency depending on magnetic field and temperature, similar to a mode in superfluid helium-3.

Contribution

It introduces a novel orbital magnetization mode in d+id' superconductors and analyzes its frequency dependence on magnetic field and temperature.

Findings

Existence of a new orbital magnetization mode in d+id' superconductors.

Mode frequency is tunable via magnetic field, proportional to B and the order parameter magnitude.

Estimated mode velocity as a function of field and temperature.

Abstract

We consider a superconducting state with a mixed symmetry order parameter components, e.g. d+is or d+id' with d'= d_{xy}. We argue for the existence of the new orbital magnetization mode which corresponds to the oscillations of relative phase \phi between two components around an equilibrium value of \phi = \pi/2. It is similar to the so called ``clapping'' mode in superfluid 3He-A. We estimate the frequency of this mode \omega_0(B,T) depending on the field and temperature for the specific case of magnetic field induced d'= d_{xy} state. We find that this mode is tunable with an applied magnetic field with \omega_0(B,T) \propto B D_0, where D_0 is the magnitude of the d-wave order parameter. We also estimate the velocity s(B,T) of this mode.