Magnonic Superradiant Phase Transition
arXiv:2007.13263 · doi:10.1038/s42005-021-00785-z
Abstract
We show that the low-temperature phase transition in ErFeO3 that occurs at a critical temperature of ~ 4 K can be described as a magnonic version of the superradiant phase transition (SRPT). The role of photons in the quantum-optical SRPT is played by Fe magnons, while that of two-level atoms is played by Er spins. Our spin model, which is reduced to an extended Dicke model, takes into account the short-range, direct exchange interactions between Er spins in addition to the long-range Er-Er interactions mediated by Fe magnons. By using realistic parameters determined by recent terahertz magnetospectroscopy and magnetization experiments, we demonstrate that it is the cooperative, ultrastrong coupling between Er spins and Fe magnons that causes the phase transition. This work thus proves ErFeO3 to be a unique system that exhibits a SRPT in thermal equilibrium, in contrast to previous observations of laser-driven non-equilibrium SRPTs.
24 pages, 9 figures
References in corpus (14)
- Strongly coupled magnons and cavity microwave photons
- Hybridizing ferromagnetic magnons and microwave photons in the quantum limit
- High Cooperativity Cavity QED with Magnons at Microwave Frequencies
- Is there a no-go theorem for superradiant quantum phase transitions in cavity and circuit QED ?
- Theory of Photon Condensation in a Spatially-Varying Electromagnetic Field
- Some remarks on 'superradiant' phase transitions in light-matter systems
- Superradiant phase transition in electronic systems and emergent topological phases
- Ultrastrong Magnon-Magnon Coupling Dominated by Antiresonant Interactions
- Adequacy of the Dicke model in cavity QED: a counter-"no-go" statement
- Drude weight, cyclotron resonance, and the Dicke model of graphene cavity QED
- Jahn-Teller systems from a cavity QED perspective
- Stability of polarizable materials against superradiant phase transition
- Quantum Critical Paraelectrics and the Casimir Effect in Time
- Terahertz Strong-Field Physics without a Strong External Terahertz Field