Structural and electronic properties of hexagonal yttrium trihydride

Journal Article · Wed Mar 15 04:00:00 EST 1995 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.51.7500· OSTI ID:6495360

Wang, Y; Chou, M Y ^[1]

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1. School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States)

The structural and electronic properties of yttrium trihydride with metal atoms in the hexagonal-close-packed (hcp) structure are studied by the pseudopotential method within the local-density-functional approximation (LDA). It is found that the hydrogen positions within the metal lattice have a major role in determining these properties. Calculations confirmed that hexagonal YH[sub 3] with unusual wavelike hydrogen displacements (space group [ital D][sub 3[ital d]][sup 4] or [ital P][bar 3][ital c]1) is energetically more stable than the cubic structure. This result is consistent with neutron-diffraction data for YD[sub 3] and for a heavy rare-earth trihydride HoD[sub 3]. These hydrogen displacements are identified as Peierls-like distortions in this three-dimensional system. The calculated final LDA band structure for YH[sub 3] gives a semimetal rather than a semiconductor. With electron and hole pockets overlapping around the [Gamma] point, the system is highly unstable. Other possible symmetry-breaking-distortion and many-body effects such as excitonic condensation are discussed.

• DOE Contract Number: FG05-90ER45431
• OSTI ID: 6495360
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:12; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ANALYTICAL SOLUTION
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTRONIC STRUCTURE
ELEMENTS
HEXAGONAL LATTICES
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
NONMETALS
SEMIMETALS
SPACE GROUPS
SYMMETRY BREAKING
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM HYDRIDES