Theoretical Study of Possible Iridium Ditelluride Phases Attainable under High Pressure

We examined the feasibility of preparing new high-pressure polymorphs of IrTe2 by determining the relative energies and unit cell volumes of known and hypothetical forms of IrTe2 on the basis of first-principles electronic band structure calculations using the Vienna ab initio simulation package (VASP). The IrTe2 polymorphs included in our analysis are three known phases, i.e., the polymeric CdI2-type, pyrite-type, and monoclinic IrTe2 phases, as well as four hypothetical phases, i.e., ramsdelite-type, pyrolusite-type, IrS2-type, and marcasite-type phases. The charge balances of these IrTe2 phases were analyzed by carrying out extended Hückel tight-binding electronic band structure calculations for the crystal structures optimized by VASP calculations.