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Possible effects of charge frustration in NaxCoO2: Bandwidth suppression, charge orders, and resurrected resonating valence bond superconductivity

Motrunich, O. I. and Lee, Patrick A. (2004) Possible effects of charge frustration in NaxCoO2: Bandwidth suppression, charge orders, and resurrected resonating valence bond superconductivity. Physical Review B, 69 (21). Art. No. 214516. ISSN 0163-1829. http://resolver.caltech.edu/CaltechAUTHORS:MOTprb04a

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Abstract

Charge frustration due to further neighbor Coulomb repulsion can have dramatic effects on the electronic properties of NaxCoO2 in the full doping range. It can significantly reduce the effective mobility of the charge carriers, leading to a low degeneracy temperature epsilonF<~T. Such strongly renormalized Fermi liquid has rather unusual properties—from the point of view of the ordinary metals with epsilonFT—but similar to the properties that are actually observed in the NaxCoO2 system. For example, we show that the anomalous thermopower and Hall effect observed in Na0.7CoO2 may be interpreted along these lines. If the repulsion is strong, it can also lead to charge order; nevertheless, away from the commensurate dopings, the configurational constraints allow some mobility for the charge carriers, i.e., there remains some "metallic" component. Finally, the particularly strong bandwidth suppression around the commensurate x = 1/3 can help resurrect the resonating valence bond superconductivity, which would otherwise not be expected near this high doping. These suggestions are demonstrated specifically for a tJ-like model with an additional nearest-neighbor repulsion.


Item Type:Article
Additional Information:©2004 The American Physical Society (Received 30 October 2003; revised 21 January 2004; published 25 June 2004) The authors are grateful to A. Vishwanath, C. Honerkamp, and T. Senthil for many useful discussions, and to N.P. Ong for making experimental results available before publication. This work was supported by the National Science Foundation under Grants No. DMR-0201069 and DMR-0213282.
Subject Keywords:sodium compounds; Fermi liquid; carrier mobility; thermoelectric power; Hall effect; strongly correlated electron systems
Record Number:CaltechAUTHORS:MOTprb04a
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:MOTprb04a
Alternative URL:http://dx.doi.org/10.1103/PhysRevB.69.214516
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7100
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:09 Jan 2007
Last Modified:26 Dec 2012 09:29

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