Critical behavior of the Hall conductivity near the percolation threshold in granular Sn: Ar mixtures

We have measured for the first time the Hall conductivity on the metallic side of the metal-insulator transition in a percolating system as a function of the metal volume fraction v. The Hall coefficient RH in granular Sn: Ar mixtures diverges as RH∝(v-vc)^-g with the critical volume fraction vc=0.26±0.01 and the critical exponent g=0.49±0.07. The experimental value of g is compared with different existing theoretical estimates and calculations of g, respectively.