An effect of the uniaxial strain on the temperature of Bose–Einstein condensation of the intersite bipolarons

We have studied an effect of uniaxial strain to the temperature of Bose–Einstein condensation of intersite bipolarons within the framework of extended Holstein–Hubbard model. Uniaxial lattice strains are taken into an account by introducing a generalized density–displacement type force for electron–lattice interaction. Associating the superconducting critical temperature Tc with the temperature of Bose–Einstein condensation TBEC of intersite bipolarons we have calculated strain derivatives of TBEC and satisfactorily explained the results of the experiments on La-based high-Tc films.

Research highlights► Theoretical model is proposed to study an effect of strain (pressure) to the temperature of Bose–Einstein condensation of the intersite bipolarons. ► Uniaxial strain dependences of the temperature of Bose–Einstein condensation of the intersite bipolarons are studied. ► Uniaxial pressure experiments results for La-based high-Tc cuprates are explained within proposed model.