Spin scattering mechanism as the origin of the T-linear resistivity in the Bi2201 system

Samples of Bi2201 single crystals with various carrier concentrations from the overdoped to the underdoped region are obtained. The normal-state resistivity and thermoelectric power (TEP) for these crystals are measured. The resistivity measurement shows that a MI transition takes place with decreasing oxygen content by heat treatment. An interesting phenomenon in the ρ-T curves is that the resistivity for the sample treated under low oxygen partial pressure deviates downward from T-linearity at 160 K. The corresponding anomaly in TEP has also been observed, i.e., the TEP exhibits a strong enhancement at 160 K, which is suggested to be associated with the opening of a spin gap. The scattering of spin fluctuation as the origin of the T-linear resistivity in the Bi2201 system is proposed and discussed in this paper.