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Title: Structural, elastic, and lattice dynamic stability of yttrium selenide (YSe) under pressure: A first principle study

Structural, elastic, and lattice dynamical stability of YSe has been investigated as a function of pressure through first principles electronic band structure calculations. The comparison of enthalpies of rocksalt type (B1) and CsCl type cubic (B2) structures determined as a function of pressure suggests that the B1 phase will transform to B2 structure at ∼32 (30 GPa at 300 K obtained from comparison of Gibbs free energy at 300 K). The transition is identified to be of first order in nature with a volume discontinuity of ∼6.2% at the transition pressure. Furthermore, the theoretically determined equation of state has been utilized to derive various physical quantities, such as zero pressure equilibrium volume, bulk modulus, and pressure derivative of bulk modulus. The single crystal elastic constants have been predicted at various pressures for both the B1 and B2 structures using the energy strain method. The activation barrier between B1 and B2 phases calculated at transition point is ∼19.7mRy/formula unit. Our lattice dynamic calculations show that both the B1 as well as B2 structures are lattice dynamically stable not only at ambient pressure but also at transition pressure. The B1 phase becomes lattice dynamically unstable at ∼112 GPa, i.e., much beyond the transition pressure. Themore » effect of temperature on volume and bulk modulus of the YSe in B1 phase has also been examined.« less
Authors:
; ;  [1]
  1. Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
Publication Date:
OSTI Identifier:
22402653
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CESIUM CHLORIDES; COMPARATIVE EVALUATIONS; ENTHALPY; EQUATIONS OF STATE; EQUILIBRIUM; FREE ENTHALPY; MONOCRYSTALS; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; STABILITY; STRAINS; YTTRIUM