Hall effect measurement in the diamond anvil high-pressure cell

Hall effect measurements have been carried out in the diamond anvil cell to pressures of 6 GPa. A plasma sprayed coating has been used to insulate the electrical leads from the gasket, similar to the configuration employed by Tozer and King [Rev. Sci. Instrum. 56, 260 (1985)], but a van der Pauw geometry was used to make the Hall and mobility measurements. Application of the technique to GaAs at 300 K is described, for which the Γ-X conduction band crossover is observed at 4.0 GPa, in good agreement with recent photoluminescence measurements.