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Title: Elastic anisotropy, vibrational, and thermodynamic properties of U{sub 2}Ti intermetallic compound with AlB{sub 2}-type structure under high pressure up to 100 GPa

Structural, elastic anisotropy, dynamical, and thermodynamic properties of U{sub 2}Ti have been studied by employing density functional theory and density functional perturbative theory. The optimized lattice parameters a, c, unit volume V, bulk modulus B, and bond lengths d{sub U-U}, d{sub U-Ti} of U{sub 2}Ti are in favorable agreement with the available experimental data and other theoretical values. The elastic constants under pressure were obtained using “energy-strain” method. The polycrystalline modulus, Poisson's ratio, brittle/ductile characteristics, Debye temperature and the integration of elastic wave velocities over different directions, and hardness under pressure are also evaluated successfully. The anisotropy of the directional bulk modulus and the Young's modulus is systematically predicted for the first time. It turns out that U{sub 2}Ti should be stabilized mechanically up to 100 GPa, this compound just possesses slightly elastic anisotropy at zero pressure; however, the anisotropy becomes more and more significant with the increasing pressure. In particular, the phonon dispersion curves and phonon density of state under pressure are reported for the first time. The Raman and infrared-active phonon modes at Γ point are further assigned. Our results indicate that U{sub 2}Ti is also stable dynamically up to 100 GPa. Additionally, within the calculated phonon density of states,more » the thermodynamic properties are predicted.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ; ; ;  [3]
  1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)
  2. (China)
  3. Key Laboratory of Neutron Physics, Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China)
Publication Date:
OSTI Identifier:
22399368
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM BORIDES; ANISOTROPY; BOND LENGTHS; DEBYE TEMPERATURE; DENSITY FUNCTIONAL METHOD; DENSITY OF STATES; HARDNESS; INTERMETALLIC COMPOUNDS; LATTICE PARAMETERS; PHASE DIAGRAMS; PHONONS; POLYCRYSTALS; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; STRAINS; THERMODYNAMIC PROPERTIES; TITANIUM; URANIUM; YOUNG MODULUS