Superlight small bipolarons from realistic long-range Coulomb and Frohlich interactions
journal contributionposted on 2013-01-31, 14:15 authored by A.S. Alexandrov, John Samson, G. Sica
We report analytical and numerical results on the two-particle states of the polaronic t-Jp model derived recently with realistic Coulomb and electron-phonon (Fr¨ohlich) interactions in doped polar insulators. Eigenstates and eigenvalues are calculated for two different geometries. Our results show that the ground state is a bipolaronic singlet, made up of two polarons. The bipolaron size increases with increasing ratio of the polaron hopping integral t to the exchange interaction Jp but remains small in the whole range 0 t/Jp 1. Furthermore, the model exhibits a phase transition to a superconducting state with a critical temperature well in excess of 100K since the small bipolarons are perfectly mobile. In the range t/Jp 1, there are distinct charge and spin gaps opening in the density of states, specific heat, and magnetic susceptibility well above Tc.
CitationALEXANDROV, A.S., SAMSON, J.H. and SICA, G., 2012. Superlight small bipolarons from realistic long-range Coulomb and Frohlich interactions. Physical Review B, 85 (10), 104520 (4pp.).
Publisher© Americal Physical Society
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