Europhys. Lett.
Volume 63, Number 4, August 2003
Page(s) 583 - 589
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00569-0
Europhys. Lett., 63 (4) , pp. 583-589 (2003)

Two-dimensional feature of the Nernst effect in normal state of underdoped $\chem{La}$ 2-x $\chem{Sr}$ x $\chem{CuO_4}$ single crystals

H. H. Wen1, Z. Y. Liu1, Z. A. Xu2, Z. Y. Weng3, F. Zhou1 and Z. X. Zhao1

1  National Laboratory for Superconductivity, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences P.O. Box 603, Beijing 100080, PRC
2  Physics Department, Zhejiang University - Zhejiang, PRC
3  Center for Advanced Study, Tsinghua University - Beijing 100084, PRC

(Received 14 March 2003; accepted in final form 18 June 2003)

The Nernst effect has been measured for an underdoped and an optimally doped $\chem{La}$ 2-x $\chem{Sr}$ x $\chem{CuO_4}$ single crystal with the magnetic field applied along different directions. For both samples, when $H\parallel c$, a significant Nernst voltage appears above $T_{\ab{c}}$ and keeps measurable up to a high temperature (100 $\un{K}$). However, when $H
\parallel ab$ -plane the Nernst signal along the c-axis drops below the noise level quickly above $T_{\ab{c}}$ for the underdoped sample. Moreover, the in-plane Nernst data with field at different angles shows a nice scaling behavior with the c-axis component of the field. All these give a strong indication for a 2D feature of the Nernst signal in the normal state of underdoped cuprate superconductors.

74.40.+k - Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.).
74.25.Fy - Transport properties (electric and thermal conductivity, thermoelectric effects, etc.).
74.72.Dn - $\chem{La}$-based cuprates.

© EDP Sciences 2003