Thermal squeezing and nonlinear spectral shift of magnons in antiferromagnetic insulators

We investigate the effect of magnon-magnon interactions on dispersion and polarization magnons in collinear antiferromagnetic (AF) insulators at finite temperatures. In two-sublattice AF systems with either uniaxial or biaxial magnetocrystalline anisotropies, we implement a self-consistent Hartree-Fock mean-field approximation to explore nonlinear thermal interactions. The resulting magnon separate into two-magnon intra- interband scattering processes. Furthermore, compute temperature dependence bandgap resonance modes due for square hexagonal lattices. addition, study modes. find that although noninteracting eigenmodes case are circularly polarized, but presence local U(1) symmetry Hamiltonian is broken. attractive squeeze low-energy make them elliptical. case, other hand, bare low energy elliptically polarized further. Direct measurements predicted temperature-dependent their can be used as tool probe Our findings establish framework exploring technologically important magnetic systems, such stability recently discovered two-dimensional materials, coherent transport magnons, Bose-Einstein condensation magnonic topological insulators.