Superlight small bipolarons from realistic long-range Coulomb and Fröhlich interactions

Abstract

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 (Frohlich) 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 compared to the system size 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. 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.

Calculation section and discussion of gap have been updated. Revised calculations now enhance the predicted T_c in our model to over 200 K at large hopping

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Cited by in corpus (4)

• Nonequilibrium propagation and decay of a bound pair in driven t-J models
• Strongly bound yet light bipolarons for double-well electron-phonon coupling
• "Quantum bipolaron" superconductivity from quadratic electron-phonon coupling
• High temperature superconductivity from realistic long-range Coulomb and Fröhlich interactions