Abstract
We present two distorted face-centered cubic (dfcc) structures of yttrium under high pressure, which have been found by a first-principles genetic algorithm technique. The structures are a tetragonal P43 (dfcc-I) and a triclinic P1¯ (dfcc-II), formed by slight distortions from a trigonal R3¯m structure reported as the dfcc phase earlier. The enthalpy difference between the two dfcc structures is less than 0.2 mRy/atom, and dfcc-I is marginally more stable than dfcc-II in lower pressure region. The enthalpy comparison among candidate structures indicates the structural phase transitions into dfcc-I at 41 GPa, into dfcc-II at 81 GPa, and into an orthorhombic Fddd structure at 106 GPa.
Acknowledgements
The work was supported by the Japan Society for the Promotion of Science (JSPS) through its ‘Funding Program for Next Generation World-Leading Researchers (NEXT Program)’ No. GR068 and ‘KAKENHI’ Nos. 25800218 and 2600006.
Notes
† This paper was presented at the LIIth European High Pressure Research Group (EHPRG 52) Meeting in Lyon (France), 7–12 September 2014.