Title
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Orientational charge density waves and the metal-insulator transition in polymerized KC60
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Author
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Abstract
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Polymerized KC60 undergoes a structural phase transition accompanied by a metal-insulator transition around 50 K. To explain the structural aspect, a mechanism involving small orientational deviations of the valence electron density on every C-60 monomer orientational charge density waves (OCDWs) - has already been proposed earlier. In the present work, we address the metal-insulator transition using the OCDW concept. We are inspired by the analogy between a polymer chain exhibiting an OCDW and a linear atomic chain undergoing a static lattice deformation doubling the unit cell: such a deformation implies a band gap at the zone boundary, yielding an insulating state (Peierls instability). Within our view, a similar mechanism occurs in polymerized KC60; the OCDW plays the role of the lattice deformation. We present tight-binding band structure calculations and conclude that the metal-insulator transition can indeed be explained using OCDWs, but that the threedimensionality of the crystal plays an unexpected key role. |
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Language
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English
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Source (journal)
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AIP conference proceedings / American Institute of Physics. - New York
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Publication
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New York
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2004
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ISSN
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0094-243X
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Volume/pages
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723
(2004)
, p. 339-342
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ISI
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000224699400072
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