Despite the extensive experimental and theoretical characterization of the band structures of III-V zincblende semiconductors, the literature is still ambiguous in classifying the symmetries of the lowest conduction states at the X point in the Brillouin zone of these compounds. We present the symmetries of these states obtained by the first principles pseudopotential and the LMTO methods and consistently label them for this class of compounds. We also point out that analyses of the indirect optical absorption edge structure in compounds with lowest conduction states at X like AlAs, AlSb and GaP reveal the symmetries of these states in agreement with theoretical predictions. This technique could also be used to determine these symmetries in other indirect gap compounds or those which acquire an indirect gap Γ → X under reasonably modest pressures like GaAs.
Bibliographical noteFunding Information:
Acknowledgement RMW acknowledgesC onselho Nacionald e DesenvolvimenCtoie nti'ficoe Tecnol6gico, CNPq, from Brazil for financial support in the initial stageso f this work. MC would like to thank the Miller ResearchIn stitutefo r the generoussu pporto f his stay at Berkeleya nd the Staffo f the PhysicsD epartmenatt UCB for overwhelminhgo spitality. This work was supported by NSF Grant No. DMR8319024a nd by the Director, Office of EnergyR esearchO, ffice of Basic Energy Sciences,M aterialS cienceD ivisiono f the U. S. Department of Energy under Contract No. DE-AC03-76SF00098. Cray computetri me was providedb y the Office of the EnergyR esearcho f the Departmenotf Energy.