Low-Temperature Normal-State Hall Effect in HIGH-Tc Bi2Sr2-xLaxCuO6+δ Revealed by 60 T Magnetic Fields

We report low-temperature Hall coefficient in the normal state of the high-T_c superconductor Bi₂Sr_2-xLa_xCuO_6+δ. The Hall coefficient was measured down to 0.5 K by suppressing superconductivity with a 60 T pulsed magnetic field. The carrier concentration was varied from overdoped to underdoped regimes by partially substituting Sr with La in a set of five samples. The observed saturation of the Hall coefficient at low temperatures suggests the ability to extract the carrier concentration of each sample. The most underdoped sample exhibits a diverging Hall coefficient at low temperatures, consistent with a depletion of carriers in the insulating ground state. The Hall number exhibits a sharp peak providing additional support for the existence of a phase boundary at the optimal doping.