Location of theL1andX3Minima in GaAs as Determined by Photoemission Studies

Direct experimental evidence for the location of the $L_1$ conduction-band minima in GaAs at 0.09±0.02 eV above the $X_1$ minima has been obtained using newly developed second-derivative methods for measuring electron energy distribution of photoemitted electrons with high resolution. The $X_3$ conduction-band minima have also been located at 0.58±0.04 eV above the $X_1$ conduction-band minima, in close agreement with recent orthogonalized-plane-wave band-structure calculations.