Band inversion and transport properties ofLminima inn−GaSb(Te)

Electrical transport measurements have been made on tellurium-doped $n$-type GaSb in the temperature range between 1.4 to 300°K and at hydrostatic pressures up to ∼ 13 kbar. Samples with concentration in the range ∼ 2 × ${10}^{17}$ to ∼ 7 × ${10}^{18}$ ${\mathrm{cm}}^{-3\mathrm{}}$ were investigated. At the highest pressures, the results suggest complete carrier transfer from the $\Gamma$ minimum into the $L$ minima or into impurity levels associated with the $L$ minima. The existence of the levels is confirmed by the observation of impurity conduction at low temperatures and deionization effects at elevated temperatures. An impurity activation energy of ${\epsilon }_1=13.8\mathrm{}$ meV is seen for the tellurium donors in the lowest-concentration sample; the activation energy decreases with increasing concentration but remains nonzero in the highest-concentration sample. Weak-field magnetoresistance anisotropy was observed, and the relations $b+c=0\mathrm{}$ and $d>\mathrm{}0\mathrm{}$ for the inverted Seitz coefficients were found to hold at high pressures in the temperature range where $L$-band conduction is expected. Calculations indicate that in highly doped samples, acoustic mode scattering dominates at 300°K, whereas at 77°K the $L$-band carrier scattering is mainly due to ionized impurities. The results obtained for pressures insufficient to produce complete thermal decoupling between the $\Gamma$ minimum and the Te levels associated with the $L$ minima are shown to be predictable using a band model employed by Kosicki and Paul.