Spectroscopic signatures of time-reversal symmetry breaking superconductivity

The collective mode spectrum of a symmetry-breaking state, such as a superconductor, provides crucial insight into the nature of the order parameter. In this work, we study two collective modes which are unique to unconventional superconductors that spontaneously break time reversal symmetry. We show that these modes are coherent and underdamped for a wide variety of time-reversal symmetry breaking superconducting states. By further demonstrating that these modes can be detected using a number of existing experimental techniques, we propose that our work can be leveraged as a form of collective mode spectroscopy that drastically expands the number of experimental probes capable of detecting time-reversal symmetry breaking in unconventional superconductors. Variations in unconventional superconductors are increasing in number and diversity in recent years, and so it is increasingly important to develop analytical methods to distinguish and categorise their different features. Here, the authors study two types of collective modes of the order parameter unique to time-reversal symmetry breaking superconductors and propose using them to identify these exotic states.

Automated summary

This study investigates two unique collective modes of order parameters in time-reversal symmetry breaking superconductors and proposes using them to identify these exotic states.