PDF characterizes competition at the nanoscale between charge localized states

A new understquencheddisorderanding of the physics behind the properties of the MIT in Cu(Ir1-xCrx)2S4 is obtained by studying the local structure and generating a local phase diagram, as opposed to the more usual average phase diagram. This has translational importance as other complex electronic systems such as high temperature superconductors are likely to have similar behavior. High data throughput x-ray PDF beamlines coupled to the large number of high quality samples allows observation of nanoscale competition and presence at low temperature of Ir4+ short range ordered dimers,  phenomenology that couples to the transport properties, which escaped detection of the average structure probes. Similar principles are expected to operate in the strongly correlated electron systems.

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E. S. Bozin et al.,  “Cu(Ir1-xCrx)2S4: a model system for studying nanoscale phase coexistence at the metal-insulator transition”, Sci. Rep. 4, 4081 (2014).