Phonon-assisted insulator-metal transitions in correlated systems driven by doping

Shneyder, E., I; Zotova, M., V; Nikolaev, S., V; Ovchinnikov, S. G. / Physical Review B/


We consider how electron-phonon interaction influences the insulator-metal transitions driven by doping in a strongly correlated system. Using the polaronic version of the generalized tight-binding method, we investigate a multiband two-dimensional model taking into account both charge density displacement and transitive types of electron-lattice contributions. For adiabatic ratio tω0, we analyze a wide electron-phonon parameter range and demonstrate the relationship between transition features and such properties of the system as polaron and bipolaron crossovers, the redistribution of the spectral weight due to the multiparticle effects of Coulomb and electron-phonon interactions, orbital selectivity, flat-band formation, and pseudogap behavior of various origins.