Orbiton-magnon interplay in the spin-orbital polarons of KCuF3 and LaMnO3
AbstractWe present a quasianalytical solution of a spin-orbital model of KCuF3, using the variational method for Green's functions. By analyzing the spectra for different partial bosonic compositions as well as the full solution, we show that hole propagation needs both orbiton and magnon excitations to develop, but the orbitons dominate the picture. We further elucidate the role of the different bosons by analyzing the self-energies for simplified models, establishing that because of the nature of the spin-orbital ground state, magnons alone do not produce a full quasiparticle band, in contrast to orbitons. Finally, using the electron-hole transformation between the eg states of KCuF3 and LaMnO3 we suggest the qualitative scenario for photoemission experiments in LaMnO3.