We have studied local structure of IrTe2 by Ir L-3-edge extended x-ray absorption fine structure (EXAFS) measurements as a function of temperature to investigate origin of the observed structural phase transition at T-s similar to 270 K. The EXAFS results show an appearance of longer Ir-Te bond length (Delta R similar to 0.05 angstrom) at T < T-s. We have found Ir-Ir dimerization, characterized by distinct Ir-Ir bond lengths (Delta R similar to 0.13 angstrom), existing both above and below T-s. The results suggest that the phase transition in IrTe2 should be an order-disorder-like transition of Ir-Ir dimers assisted by Ir-Te bond correlations, thus indicating important role of the interaction between the Ir 5d and Te 5p orbitals in this transition.
Local structural displacements across the structural phase transition in IrTe 2: Order-disorder of dimers and role of Ir-Te correlations / B., Joseph; M., Bendele; L., Simonelli; Maugeri, Laura; S., Pyon; K., Kudo; M., Nohara; T., Mizokawa; Saini, Naurang Lal. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 88:22(2013). [10.1103/physrevb.88.224109]
Local structural displacements across the structural phase transition in IrTe 2: Order-disorder of dimers and role of Ir-Te correlations
MAUGERI, LAURA;SAINI, Naurang Lal
2013
Abstract
We have studied local structure of IrTe2 by Ir L-3-edge extended x-ray absorption fine structure (EXAFS) measurements as a function of temperature to investigate origin of the observed structural phase transition at T-s similar to 270 K. The EXAFS results show an appearance of longer Ir-Te bond length (Delta R similar to 0.05 angstrom) at T < T-s. We have found Ir-Ir dimerization, characterized by distinct Ir-Ir bond lengths (Delta R similar to 0.13 angstrom), existing both above and below T-s. The results suggest that the phase transition in IrTe2 should be an order-disorder-like transition of Ir-Ir dimers assisted by Ir-Te bond correlations, thus indicating important role of the interaction between the Ir 5d and Te 5p orbitals in this transition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.