Role of metal d states in II-VI semiconductors

Journal Article · Sun May 15 04:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.37.8958· OSTI ID:5184488

Wei, S; Zunger, A

All-electron band-structure calculations and photoemission experiments on II-VI semiconductors both exhibit a metal d subband inside the main valence band. It has nevertheless been customary in pseudopotential and tight-binding approaches to neglect the metal d band by choosing Hamiltonian parameters which place this band inside the chemically inert atomic cores. Using all-electron self-consistent electronic-structure techniques (which treat the outermost d electrons on the same footing as other valence electrons) and comparing the results to those obtained by methods which remove the d band from the valence spectrum, we study their effects on valence properties. For II-VI semiconductors we find that p-d repulsion and hybridization (i) lower the band gaps, (ii) reduce the cohesive energy, (iii) increase the equilibrium lattice parameters, (iv) reduce the spin-orbit splitting, (v) alter the sign of the crystal-field splitting, (vi) increase the valence-band offset between common-anion II-VI semiconductors, and (vii) modify the charge distributions of various II-VI systems and their alloys. p-d repulsion is also shown to be responsible for the occurrence of deep Cu acceptor levels in II-VI semiconductors (compared with shallow acceptors of Zn in III-V), for the anomalously small band gaps in chalcopyrites, and for the negative exchange splitting in ferromagnetic MnTe.

• Research Organization: Solar Energy Research Institute, Golden, Colorado 80401
• DOE Contract Number: AC02-77CH00178
• OSTI ID: 5184488
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 37:15; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CHALCOGENIDES
COUPLING
CRYSTAL FIELD
D STATES
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY GAP
ENERGY LEVELS
EXCHANGE INTERACTIONS
HYBRIDIZATION
INTERACTIONS
INTERMEDIATE COUPLING
L-S COUPLING
LATTICE PARAMETERS
MANGANESE COMPOUNDS
MANGANESE TELLURIDES
MATERIALS
METALS
SELF-CONSISTENT FIELD
SEMICONDUCTOR MATERIALS
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VALENCE