Europhys. Lett.
Volume 69, Number 2, January 2005
Page(s) 263 - 269
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 17 December 2004
Europhys. Lett., 69 (2), pp. 263-269 (2005)
DOI: 10.1209/epl/i2003-10315-8

Bulk evidence for $\mth{s}$-wave pairing symmetry in electron-doped infinite-layer cuprate $\chem{Sr_{0.9}La_{0.1}CuO_{2}}$

Z. Y. Liu1, H. H. Wen1, L. Shan1, H. P. Yang1, X. F. Lu1, H. Gao1, Min-Seok Park2, C. U. Jung2 and Sung-Ik Lee2

1  National Laboratory for Superconductivity, Institute of Physics Chinese Academy of Sciences - P.O. Box 603, Beijing 100080, PRC
2  National Creative Research Initiative Center for Superconductivity and Department of Physics, Pohang University of Science and Technology Pohang 790-784, Republic of Korea

received 14 October 2003; accepted in final form 8 November 2004
published online 17 December 2004

The low-temperature specific heat of electron-doped (n-type) infinite-layer cuprate superconductor $\chem{Sr_{0.9}La_{0.1}CuO_{2}}$ was measured. The quasiparticle density of states (DOS) in the mixed state is found to be consistent with the predictions of the s-wave pairing symmetry, and agree very well with the earlier results from tunnelling measurement. This is contrary to the prediction of d-wave symmetry, which has been confirmed for the hole-doped (p-type) cuprates. Our results indicate that the electronic DOS in the mixed state are mainly contributed by the vortex core area in the present sample.

74.20.Rp - Pairing symmetries (other than s-wave).
74.25.Bt - Thermodynamic properties.
74.72.Dn - La-based cuprates.

© EDP Sciences 2005