Abstract.
We present the optical properties of Na0.7CoO2 single crystals, measured over a broad spectral range as a function of temperature (T). The capability to cover the energy range from the far-infrared up to the ultraviolet allows us to perform reliable Kramers-Kronig transformation, in order to obtain the absorption spectrum (i.e., the complex optical conductivity). To the complex optical conductivity we apply the generalized Drude model, extracting the frequency dependence of the scattering rate (\(\Gamma\)) and effective mass (m *) of the itinerant charge carriers. We find that \(\Gamma(\omega)\sim \omega\) at low temperatures and for \(\omega > T\). This suggests that Na0.7CoO2 is at the verge of a spin-density-wave metallic phase.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
K. Takada, H. Sakurai, E. Takayama-Muromachi, F. Izumi, R.A. Dilanian, T. Sasaki, Nature 422, 53 (2003)
M.L. Foo, Y. Wang, S. Watauchi, H.W. Zandbergen, T. He, R.J. Cava, N.P. Ong, Phys. Rev. Lett. 92, 247001 (2004)
B.C. Sales, R. Jin, K.A. Affholter, P. Khalifah, G.M. Veith, D. Mandrus, submitted to Phys. Rev. B, cond-mat/0402379
J. Sugiyama, J.H. Brewer, E.J. Ansaldo, B. Hitti, M. Mikami, Y. Mori, T. Sasaki, Phys. Rev. B 69, 214423 (2004)
T. Motohashi, R. Ueda, E. Naujalis, T. Tojo, I. Terasaki, T. Atake, M. Karppinen, H. Yamauchi, Phys. Rev. B 67, 064406 (2003)
S. Lupi, M. Ortolani, P. Calvani, Phys. Rev. B 69, 180506 (2004)
N.L. Wang, P. Zheng, D. Wu, Y.C. Ma, T. Xiang, R.Y. Jin, D. Mandrus, cond-mat/0312630
M.N. Iliev, A.P. Litvinchuk, R.L. Meng, Y. Sun, J. Cmaidalka, C.W. Chu, Physica C 402, 239 (2004)
The dc resistivity \(\rho (T)\) was measured within the ab plane and along the c-axis at EPF-Lausanne, with the conventional four points contact method
Y. Wang, N.S. Rogado, R.J. Cava, N.P. Ong, Nature 423, 425 (2003)
F. Wooten, Optical Properties of Solids (Academic Press, New York, 1972)
M. Dressel, G. Grüner, Electrodynamics of Solids (Cambridge University Press, Cambridge, 2002)
C. Bernhard, A.V. Boris, N.N. Kovaleva, G. Khaliullin, A. Pimenov, L. Yu, D.P. Chen, C.T. Lin, B. Keimer, cond-mat/0403155
M.Z. Hasan, Y.-D. Chuang, D. Qian, Y.W. Li, Y. Kong, A. Kuprin, A.V. Fedorov, R. Kimmerling, E. Rotenberg, K. Rossnagel, Z. Hussain, H. Koh, N.S. Rogado, M.L. Foo, R.J. Cava, Phys. Rev. Lett. 92, 246402 (2004)
D.J. Singh, Phys. Rev. B 61, 13397 (2000)
K.W. Lee, J. Kunes, W.E. Pickett, Phys. Rev. B 70, 045104 (2004); cond-mat/0308388
J. Hwang, T. Timusk, G.D. Gu, Nature 427, 714 (2004)
J. Ruvalds, A. Virosztek, Phys. Rev. B 43, 5498 (1991)
S.Y. Li, L. Taillefer, D.G. Hawthorn, M.A. Tanatar, J. Paglione, M. Sutherland, R.W. Hill, C.H. Wang, X.H. Chen, Phys. Rev. Lett. 93, 056401 (2004)
M.D. Johannes, I.I. Mazin, D.J. Singh, D.A. Papaconstantopoulos, cond-mat/0403135
J. Wooldridge, D.M. Paul, G. Balakrishnan, M.R. Lees, submitted to J. Phys.: Condens. Matter, cond-mat/0406513
Author information
Authors and Affiliations
Corresponding author
Additional information
Received: 6 August 2004, Published online: 9 September 2004
PACS:
78.20.-e Optical properties of bulk materials and thin films - 74.70.Dd Ternary, quaternary and multinary compounds (including Chevrel phases, borocarbides, etc.) - 75.30.Fv Spin-density waves
Rights and permissions
About this article
Cite this article
Caimi, G., Degiorgi, L., Berger, H. et al. Optical evidence for the proximity to a spin-density-wave metallic state in \(\mathsf{Na_{0.7}CoO_2}\) . Eur. Phys. J. B 40, 231–234 (2004). https://doi.org/10.1140/epjb/e2004-00275-9
Issue Date:
DOI: https://doi.org/10.1140/epjb/e2004-00275-9