Experimental energy-band dispersions, critical points, and spin-orbit splittings for GaSb using angle-resolved photoemission

We have determined energy-band dispersions $E\left(\overrightarrow{\mathrm{k}}\right)$ and critical points for GaSb using angle-resolved-photoemission techniques. With a normal emission configuration and photon energies between 24 and 95 eV, the valence-band dispersions $E\left(\overrightarrow{\mathrm{k}}\right)$ have been obtained along the $\Gamma -K-X$ direction, with the spin-orbit splitting ${\Delta }_0({\Gamma }_8-{\Gamma }_7)$ clearly observed. With an off-normal emission configuration, we have also determined the valence-band critical-point energies at the $L$ point, with the spin-orbit splitting ${\Delta }_1(L_{4,5}-L_6)$ clearly observed. Experimental valence-band critical-point energies at $\Gamma$, $X$, and $L$ are compared with recent theoretical results. Using published transition energies determined from reflectance measurements, we have also obtained the low-lying conduction-band critical-point energies. These valence- and conduction-band critical-point energies are tabulated to facilitate comparisons with other experimental and theoretical results.