Abstract
Bardasis-Schrieffer modes in superconductors are fluctuations in subdominant pairing channels, e.g., -wave fluctuations in an -wave superconductor. This Rapid Communication shows that these modes also generically occur in excitonic insulators. In -wave excitonic insulators, a -wave Bardasis-Schrieffer mode exists below the gap energy, is optically active, and hybridizes strongly with photons to form Bardasis-Schrieffer polaritons, which are observable in both far-field and near-field optical experiments.
- Received 27 March 2020
- Revised 19 June 2020
- Accepted 19 June 2020
DOI:https://doi.org/10.1103/PhysRevB.102.041110
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