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

摘要

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 T_c with the temperature of Bose-Einstein condensation T_(BEC) of intersite bipolarons we have calculated strain derivatives of T_(BEC) and satisfactorily explained the results of the experiments on La-based high-Tc films.