MULTIPHONON HOPPING TRANSPORT IN BI2CUO4 SINGLE-CRYSTAL

The d.c. electrical conductivity along c- and a, b-axes for the Bi2CuO 4 single crystal has been studied as a function of temperature for the first time. We have observed that the variable range hopping mechanis m 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 a can be described by sigma similar to T-p, where the exponent p is dependent on measuremen t axes and on the temperature range. We have interpreted the results i n the framework of the multiphonon assisted hopping theory with a weak electron-phonon coupling. (C) 1998 Elsevier Science Ltd. All rights r eserved.