Pressure dependence of the local structure of iridium ditelluride across the structural phase transition

The local structure of IrTe2 has been studied by iridium L3-edge x-ray absorption spectroscopy (XAS) measurements as a function of pressure, performed at two temperatures (100 and 295 K) across the structural phase transition at ∼270 K. Extended x-ray absorption fine structure (EXAFS) and x-ray absorption near-edge structure (XANES) spectra show pressure-dependent anomalies, suggesting phase transitions that are characterized by different local atomic displacements. The high-temperature phase of IrTe2 (trigonal at 295 K) reveals a clear anomaly in the Ir-Te correlations at ∼4 GPa, while the low-temperature phase (at 100 K) shows a smaller change at ∼6 GPa, likely to be associated with transitions in lower-symmetry phases. XANES spectra, measuring higher-order atomic correlations, also shownonlinear pressure dependence in the local geometry at the anomalous pressures. These nonlinear changes suggest that IrTe2 goes through lower local symmetry phases with increasing pressure.