Shubnikov-de Haas Oscillations inn-Type GaAs

Shubnikov-de Haas oscillations in $n$-type GaAs are reported for four samples with carrier concentrations between 2×${10}^{16}$ and 2×${10}^{17}$/${\mathrm{cm}}^3$. Temperatures employed ranged from 1.3 to 4.2°K, while magnetic fields were 34 kG and below. Scattering times were such that $0.1<\mathrm{}{\omega }_c\tau <0.9\mathrm{}$ for all measurements. Carrier concentrations derived from the oscillations agreed with Hall determinations to better than 10%. Only the fundamental oscillation in $B^{-1\mathrm{}}$ was observed, the phase angle being $\frac{1}{4}\pi$ within a considerable uncertainty forced by the extrapolation to $B^{-1\mathrm{}}=0\mathrm{}$. Amplitude variation with temperature and field for the two samples with carrier concentration greater than ${10}^{17}$/${\mathrm{cm}}^3$ was adequate to permit calculation of effective mass (0.058±0.006) and Dingle temperature (∼12°K). The magnitude of the amplitude agreed with theory to within a factor of 7.