Quasiparticle Dynamics in the Vicinity of Metal-Insulator Phase Transition in Na_xCoO_2
Abstract
Layered cobaltates embody novel realizations of correlated matter on a spin-1/2 triangular lattice. We report a high-resolution systematic photoemission study of the insulating cobaltates. The observation of a single-particle gap opening and band folding provides direct evidence of anisotropic particle-hole instability on the Fermi surface due to its unique topology. Overlap of the measured Fermi surface is observed with the 3√× 3√ charge-order Brillouin zone near x = 1/3 but not at x = 1/2 where the insulating transition is actually observed. Unlike conventional density waves, charge stripes, or band insulators, the onset of the gap depends on the quasiparticle's quantum coherence which is found to occur well below the disorder-order symmetry breaking temperature of the crystal (the first known example of its kind).
Additional Information
© 2006 The American Physical Society. Received 9 October 2005. Published 2 February 2006. We thank M. Lee for the resistivity measurements on the samples. We gratefully acknowledge D. A. Huse, M. R. Beasley, D. H. Lee, M. Lee, P. A. Lee, N. P. Ong, P. Phillips, S. Shastry, and S. A. Kivelson for discussions. This work is partially supported through the NSF-MRSEC (DMR-0213706), DOE Grants No. DE-FG02-05ER46200 and No. DE-FG02-98-ER45706, and NSFC (No. 10574158). ALS is supported by DOE/BES-DE-AC03-76SF00098.Attached Files
Published - PhysRevLett.96.046407.pdf
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Additional details
- Alternative title
- Quasiparticle Dynamics in the Vicinity of Metal-Insulator Phase Transition in NaxCoO2
- Eprint ID
- 49319
- Resolver ID
- CaltechAUTHORS:20140908-092120910
- DMR-0213706
- NSF
- DE-FG02- 05ER46200
- Department of Energy (DOE)
- DE-FG02-98-ER45706
- Department of Energy (DOE)
- 10574158
- National Science Foundation of China (NSFC)
- DE-AC03- 76SF00098
- Department of Energy (DOE)
- Created
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2014-09-08Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field