Publication Date:
2013-07-02
Description:
Nature Physics 9, 419 (2013). doi:10.1038/nphys2642 Authors: F. Kagawa, T. Sato, K. Miyagawa, K. Kanoda, Y. Tokura, K. Kobayashi, R. Kumai & Y. Murakami Geometrically frustrated spin systems often do not exhibit long-range magnetic ordering, resulting in either quantum-mechanically disordered states, such as quantum spin liquids, or classically disordered states, such as spin ices or spin glasses. Geometric frustration may play a similar role in charge ordering, potentially leading to unconventional electronic states without long-range order; however, there are no previous experimental demonstrations of this phenomenon. Here, we show that a charge-cluster glass evolves on cooling in the absence of long-range charge ordering for an organic conductor with a triangular lattice. A combination of time-resolved transport measurements and X-ray diffraction reveals that the charge-liquid phase has two-dimensional charge clusters that fluctuate extremely slowly (〈10–100 Hz) and heterogeneously. On further cooling, the cluster dynamics freezes, and a charge-cluster glass is formed. Surprisingly, these observations correspond to recent ideas regarding the structural glass formation of supercooled liquids. Glassy behaviour has often been found in transition-metal oxides, but only under the influence of randomly located dopants. As organic conductors are very clean systems, the present glassy behaviour is probably conceptually different.
Print ISSN:
1745-2473
Electronic ISSN:
1745-2481
Topics:
Physics
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