Review on distorted face-centered cubic phase in yttrium via genetic algorithm

摘要

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 P4(3) (dfcc-I) and a triclinic P1 over bar (dfcc-II), formed by slight distortions from a trigonal R3 over bar m structure reported as the dfcc phase earlier. The enthalpy difference between the two dfcc structures is less than 0.2mRy/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 41GPa, into dfcc-II at 81GPa, and into an orthorhombic Fddd structure at 106GPa.