The magnetic susceptibility of $n$-InSb has been measured for a range of extrinsic carrier densities extending from ${10}^{16}$ to 6×${10}^{18}$ ${\mathrm{cm}}^{-3\mathrm{}}$. Measurements were made in the temperature range 300°K to 1.3°K. The degenerate conduction electron susceptibility was determined from the data. The deviation of the conduction band from parabolic form is clearly exhibited in the susceptibility. A theoretical analysis has been made using Kane's band-structure calculation. The mixing of the conduction and valence bands resulting from the magnetic field has been treated exactly. Consideration of these two bands alone will not explain the dependence on concentration of the observed susceptibility; at the higher carrier densities, higher bands are important and a perturbation-theoretical treatment of these indicates that the observed susceptibility is consistent with Kane's model.

• Received 26 March 1959

DOI:https://doi.org/10.1103/PhysRev.115.1165