Total-energy and band-structure calculations for the semimagnetic Cd/sub 1-//sub x/Mn/sub x/Te semiconductor alloy and its binary constituents

Journal Article · Sun Feb 15 04:00:00 EST 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.35.2340· OSTI ID:6048141

Wei, S; Zunger, A

Spin-polarized, self-consistent local-spin density total-energy and band-structure calculations have been performed for CdTe, antiferromagnetic (AF) MnTe in its NiAs structure, ferromagnetic (F) CdMnTe/sub 2/, and the hypothetical zinc-blende phase of MnTe in the F and AF spin arrangements. We find the following: (i) The alloy environment stabilizes a zinc-blende form of MnTe, hitherto unknown to exist in the phase diagram of pure MnTe. Its calculated Mn: Te bond length (2.70 +- 0.02 A) is very close to that observed in the alloy (2.73 A), but is substantially different from the Mn: Te bond length in pure (NiAs-type) MnTe (2.92 A). (ii) AF zinc-blende MnTe is more stable than F zinc-blende MnTe due to a reduced p-d repulsion in the upper valence states. (iii) F Cd/sub 1-//sub x/Mn/sub x/Te is more stable than its zinc-blende constituents CdTe + F MnTe, hence, once formed, this ordered alloy will not disproportionate. (iv) Nevertheless, AF CdMnTe/sub 2/ is more stable than its ferromagnetic counterpart, but it is unstable relative to its constituents CdTe + AF MnTe. Hence, if F CdMnTe/sub 2/ converts into AF CdMnTe/sub 2/, the latter will disproportionate into antiferromagnetic domains of MnTe. (v) The band structure of F zinc-blende MnTe and F CdMnTe/sub 2/ predicts a novel type of negative (p-d) exchange splitting, whose origins are discussed in terms of a p-d repulsion mechanism. (vi) The calculated electronic states of Cd/sub 1-//sub x/Mn/sub x/Te show a vanishing optical bowing, a Mn d/sub up-arrow/ band at E/sub v/-2.5 eV and explains the observed optical transitions.

• Research Organization: Solar Energy Research Institute, Golden, Colorado 80401
• OSTI ID: 6048141
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 35:5; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ANGULAR MOMENTUM
ANTIFERROMAGNETIC MATERIALS
BOND LENGTHS
CADMIUM COMPOUNDS
CADMIUM TELLURIDES
CHALCOGENIDES
CHEMICAL BONDS
COVALENCE
DIMENSIONS
ELECTRONIC STRUCTURE
ENERGY
EXCHANGE INTERACTIONS
FERROMAGNETIC MATERIALS
INTERACTIONS
LENGTH
MAGNETIC MATERIALS
MAGNETIC SEMICONDUCTORS
MANGANESE COMPOUNDS
MANGANESE TELLURIDES
MATERIALS
MINERALS
ORIENTATION
PARTICLE PROPERTIES
SELF-CONSISTENT FIELD
SEMICONDUCTOR MATERIALS
SPHALERITE
SPIN
SPIN ORIENTATION
STABILITY
SULFIDE MINERALS
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS