Band gaps and spin-orbit splitting of ordered and disordered Al/sub x/Ga/sub 1-//sub x/As and GaAs/sub x/Sb/sub 1-//sub x/ alloys

Journal Article · Wed Feb 15 00:00:00 EST 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.3279· OSTI ID:6439577

Wei, S; Zunger, A

Spontaneous long-range ordering of the otherwise disordered isovalent semiconductor alloys A/sub x/B/sub 1-x/C has been recently observed in numerous III-V alloy systems exhibiting the CuAu-I, CuPt, and chalcopyrite structures. We present a theory for the ordering-induced changes in the Brillouin-zone-center electronic properties, with application to the Al/sub x/Ga/sub 1-//sub x/As and GaAs/sub x/Sb/sub 1-//sub x/ alloys. The dominant effect for these systems is shown to be level repulsion between different-symmetry states of the binary constituents which fold into equal-symmetry states in the ordered ternary structures. Strong variations in the band gaps, spin-orbit splittings, and charge densities among the three basic ordered structures reflect the different magnitudes of the symmetry-enforced coupling between the folded states. An extension of the model to the disordered alloys yields good agreement with the observed optical bowing parameters for the fundamental gaps; however, the positive (downward concave) bowing of the spin-orbit splitting observed in some common-cation semiconductor alloy remains an unexplained puzzle.

• Research Organization: Solar Energy Research Institute, Golden, Colorado 80401
• OSTI ID: 6439577
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 39:5
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ARSENIDES
ELECTRONIC STRUCTURE
GALLIUM ANTIMONIDES
GALLIUM ARSENIDES
CHALCOPYRITE
ENERGY GAP
L-S COUPLING
OPTICAL PROPERTIES
ORDER-DISORDER TRANSFORMATIONS
SEMICONDUCTOR MATERIALS
SYMMETRY
THERMODYNAMIC PROPERTIES
ALUMINIUM COMPOUNDS
ANTIMONIDES
ANTIMONY COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER SULFIDES
COUPLING
GALLIUM COMPOUNDS
INTERMEDIATE COUPLING
IRON COMPOUNDS
IRON SULFIDES
MATERIALS
MINERALS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PNICTIDES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360603* - Materials- Properties