Low-Temperature Transport Effects inn-Type GaSb at High Magnetic Fields

De Haas-van Alphen-like oscillations in the Hall coefficient and the transverse magnetoresistance have been observed in $n$-type GaSb at 4.2°K in dc magnetic fields up to 80 kG. Oscillatory behavior in both galvanomagnetic phenomena were seen not only at Fermi levels near and above the $〈111〉$ conduction-band minima, but also were found to occur at Fermi levels many $k_{\mathrm{B}}T$ below the $〈111〉$ conduction-band edge. The observed oscillatory behavior in all of the samples investigated is ascribed to the oscillatory variation of the scattering rate for electrons in the $k=0\mathrm{}$ band with changing magnetic field. The nonoscillatory component of either the Hall effect or the transverse magnetoresistance shows a significant magnetic field dependence for Fermi-level positions above the $〈111〉$ band edge; the nonoscillatory components are found to be independent of field for Fermi levels below the $〈111〉$ band edge. The behavior at Fermi levels above the $〈111〉$ band edge is attributed to two-band conduction processes; the analysis provides values of the heavy-to-light electron mobility ratio. Assuming a Kane conduction-band model, a value of 0.095 eV for the energy separation in the conduction band between the central minimum and the subsidiary $〈111〉$ valleys is derived from a comparison of the measured Hall coefficient with the Hall-coefficient values derived from the periods of the observed Hall effect and magnetoresistance oscillations.