Collective modes in excitonic insulators: Effects of electron-phonon coupling and signatures in the optical response
Yuta Murakami, Denis Golež, Tatsuya Kaneko, Akihisa Koga, Andrew J. Millis, Philipp Werner
Abstract
The spontaneous condensation of excitons into an excitonic insulator phase has been proposed to occur in several materials. However, spontaneous condensation of phonons (i.e., lattice distortions) can produce similar effects. An important open question is whether the exciton or the phonon mechanism is dominant and how phonons affect the ideal excitonic insulator. This work reveals the characteristic features of the collective excitations of coupled exciton-phonon systems and shows how this information can be used to experimentally identify the dominant condensation mechanism.
Topics & Concepts
PhononExcitonCondensed matter physicsInsulator (electricity)PhysicsLattice (music)Coupling (piping)ElectronCondensationMaterials scienceQuantum mechanicsOptoelectronicsThermodynamicsMetallurgyAcousticsPerovskite Materials and ApplicationsPhysics of Superconductivity and MagnetismAdvanced Condensed Matter Physics