Phase transformations of polymeric CdI2-type IrTe2 under high pressure Original Research Article

The high-pressure behavior of IrTe2 has been studied up to 32 GPa in a diamond anvil cell by angle-dispersive X-ray diffraction at room temperature. The CdI2-type structure was present over the whole pressure range investigated. At about 5 GPa, a new monoclinic phase appeared; however, the transformation remained incomplete. At 20 GPa, new and faint diffraction lines were detected; after laser heating at this pressure, these lines increased strongly in intensity and were easily assigned to a cubic unit cell. This phase was retained down to ambient conditions. Its structure was refined by Rietveld analysis. It is pyrite-like with Te–Te pairs. Under ambient conditions, the intrapair Te–Te distance is 3.075 Å, which is much shorter than the shortest Te–Te distance in the CdI2-type phase; this distance did not decrease appreciably with pressure in contrast to interpair distances.