Pressure-dependent magnetoreflection studies of Bi andBi1−xSbxalloys

Pressure-dependent magnetoreflection results for Bi and ${\mathrm{Bi}}_{1-x}{\mathrm{Sb}}_x$ ($x=0.05,0.15\mathrm{}$) alloys are reported for pressures up to 3 kbar at 77 K, for $\overrightarrow{\mathrm{H}}$ parallel to the binary axis and using a C${\mathrm{O}}_2$ laser source operating at 10.6 μm. The results are interpreted to yield values for the pressure dependence of the $L$-point energy gap and the band-edge cyclotron effective mass. The analysis shows that the pressure dependence of $\frac{E_g}{{m_c}^{*}}$ dominates the pressure-dependent magnetoreflection spectra, a result of significance because previous pressure-dependent Fermi-surface studies have assumed $\frac{E_g}{{m_c}^{*}}$ to be pressure independent. Furthermore, the analysis shows that the magnitudes of the individual pressure derivatives $\frac{d{E}_g}{\mathrm{dp}}$ and $\frac{d{m_c}^{*}}{\mathrm{dp}}$ are very sensitive to $\frac{d\left(\frac{E_g}{{m_c}^{*}}\right)}{\mathrm{dp}}$ for these materials.