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 ofBose-Einstein condensation of intersite bipolarons within the framework ofExtended Holstein-Hubbard model. Uniaxial lattice strains are taken into anaccount by introducing a generalized density-displacement type force forelectron-lattice interaction. Associating the superconducting criticaltemperature $T_c$ with the temperature of Bose-Einstein condensation $T_{BEC}$of intersite bipolarons we have calculated strain derivatives of $T_{BEC}$ andsatisfactorily explained the results of the experiments on La-based high-$T_c$films.