The evolution of the short-range structural signature of the Ir 4+ dimer state in CuIr2S4 thiospinel has been studied across the metal-insulator phase transitions as the metallic state is induced by temperature, Cr doping, and x-ray fluence. An atomic pair distribution function (PDF) approach reveals that there are no local dimers that survive into the metallic phase when this is invoked by temperature and doping. The PDF shows Ir4+ dimers when they exist, regardless of whether or not they are long-range ordered. At 100 K, exposure to a 98 keV x-ray beam melts the long-range dimer order within a few seconds, though the local dimers remain intact. This shows that the metallic state accessed on warming and doping is qualitatively different from the state obtained under x-ray irradiation.



Keywords and Phrases

Atomic Pair Distribution Functions; Cr-doping; Metal-insulator Phase Transition; Metallic Phase; Metallic State; Structural Signatures; X Ray Beam; X Ray Irradiation; X-ray Fluence; Chromium; Dimers; Iridium; Metal Insulator Boundaries; Metal Insulator Transition; Semiconductor Insulator Boundaries; Distribution Functions

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

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© 2011 American Physical Society (APS), All rights reserved.

Publication Date

01 Jan 2011

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Physics Commons