Structural and electronic properties of hexagonal yttrium trihydride

Journal Article · Wed Mar 15 00:00:00 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), Vol. 51:12; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

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