Multiphonon hopping transport in Bi₂CuO₄ single crystal

Abstract

The d.c. electrical conductivity along c- and a, b-axes for the Bi₂CuO₄ single crystal has been studied as a function of temperature for the first time. We have observed that the variable range hopping mechanism cannot dominate the charge transport process in Bi₂CuO₄, unlike the rare earth cuprate La₂CuO₄. On the contrary, we have observed that the temperature dependence of the d.c. conductivity s can be described by σ ~T^p, where the exponent p is dependent on measurement axes and on the temperature range. We have interpreted the results in the framework of the multiphonon assisted hopping theory with a weak electron-phonon coupling.