Hall effect and band structure of p-CdSb in strong magnetic field

摘要

The Hall effect in the anisotropic II―V group semiconductor p-CdSb is investigated at temperatures between T = 3.6 and 200 K and pulsed magnetic fields up to B = 25 T in unintentionally doped samples oriented along the crystallographic axes [100] and [010]. The Hall coefficient, R(B, T), with B || [001] exhibits in low fields a flat region followed by a descending interval when B is increased. This behaviour is attributed to the presence of two groups of holes with concentrations p_2(T) > p_1(T) and mobilities μ_2(T) < μ(T), respectively. The analysis of p_1(T) and p_2(T) demonstrates that below T_(cr) ～ 20 K and down to ～6-7 K the low-mobility carriers pi are itinerant holes in a deeper acceptor band A_2 with an energy E_2≈6 meV. The high-mobility carriers p_2 are at all temperatures T < T_(cr) holes activated thermally from A_2 to itinerant states of a shallower acceptor band A_1 with an energy E_1 ≈ 3 meV. At T > T_(cr)p_1 and p_2 are related to the holes activated to the light- and heavy-hole bands, respectively. The analysis of μ_1 (T) and μ_2(T) confirms the existence of the heavy-hole band or a non-equivalent maximum and two equivalent maxima of the light-hole valence band.