Abstract
WO3 crystals were doped with Na on the surface to ∼7% nominal atomic concentration. Scanning tunneling microscopy and spectroscopy were employed, together with magnetization measurements, in the study of these crystals. Tunneling experiments reveal superconducting islands, 20–150 nm in size, covering about 10% of the surface, the rest of which is insulating. Magnetization measurements show that the superconducting phase formed at the surface has a critical temperature of 91 K, while tunneling spectroscopy yields superconducting gaps having values up to 2Δ/kT c ∼ 4. Presumably most of the sodium is concentrated in these islands and therefore they are metallic in nature, above 30% in atomic concentration. This material is therefore a noncuprate superconductor with a high critical temperature.
Similar content being viewed by others
References
D. Saint-James and P. G. de Génnes Phys. Lett. 7, 306 (1963).
V. L. Ginzburg and D. A. Kirzhnits, Sov. Phys. JETP 19, 269 (1964).
V. L. Ginzburg, Phys. Scripta T27, 76 (1989).
B. T. Matthias, Phys. Rev. 76, 430 (1949).
V. E. Henrich and P. A. Cox, in The Surface Science of Metal Oxides (Cambridge University Press, Cambridge, 1994), p. 241.
G. Hollinger, P. Pertosa, J. P. Doumerc, F. J. Himpsel, and B. Reihl, Phys. Rev. B 32, 1987 (1985).
Ch. J. Raub, A. R. Sweedler, M. A. Jensen, and B. T. Matthias, Phys. Rev. Lett. 13, 746 (1964).
A. W. Sleight, in Concise Encyclopedia of Magnetic and Superconducting Materials, J. Evetts, ed. (Pergamon Press, New York, 1992), p. 423.
A. Aird and E. K. H. Salje, J. Phys. Condens. Matter 10, L377 (1998).
A. Aird, M. C. Domeneghetti, F. Mazzi, V. Tazzoli, and E. K. H. Salje, J. Phys. Condens. Matter 10, L569 (1998).
S. Reich and Y. Tsabba, Eur. Phys. J. B 9, 1 (1999).
A. Shengelaya, S. Reich, Y. Tsabba, and K. A. Muller, Eur. Phys. J. B 12, 13 (1999).
M. Tinkham, Introduction to Superconductivity (McGraw–Hill, Malabar, 1975), Chap. 2.
I. Sangaletti, L. E. Depero, E. Bontempi, R. Salari, and G. Sberveglieri, J. Solid State Chem. 131, 215 (1997).
S. Hayashi, H. Sugano, H. Arai, and K. Yamamoto, J. Phys. Soc. Jap. 61, 916 (1992).
G. Deutscher and P. G. de Gennes, in Superconductivity, R. D. Parks, ed. (Dekker, New York, 1969), Vol. 2.
S. H. Tessmer, D. J. Van Harlingen, and J. W. Lyding, Phys. Rev. Lett, 7 3135 (1993); S. H. Tessmer, M. B. Tarlie, D. J. Van Harlingen, D. L. Maslov, and P. M. Goldbart, Phys. Rev. Lett 77, 924 (1996).
Y. Levi, O. Millo, N. D. Rizzo, D. E. Prober, and L. R. Motowidlo, Phys. Rev. B 58, 15128 (1998).
Y. Levi, I. Felner, U. Asaf, and O. Millo, Phys. Rev. B 60, R15059 (1999).
E. L. Wolf, Principles of Electron Tunneling Spectroscopy (Oxford University Press, Oxford, 1985), Chap. 3.
R. C. Dynes, V. Narayanamurti, and P. J. Garno, Phys. Rev. Lett. 41, 1509 (1978).
Gueron, H. Pothier, N. O. Birge, D. Esteve, and M. H. Devoret, Phys. Rev. Lett. 77, 3025 (1996).
A. E. Hanna and M. Tinkham, Phys. Rev. B 43, 5919 (1991).
E. Bar-Sadeh, I. Felner, U. Asaf, and O. Millo, Phys. Rev. B 52, 6734 (1995).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Reich, S., Leitus, G., Tssaba, Y. et al. Localized High-Tc Superconductivity on the Surface of Na-Doped WO3. Journal of Superconductivity 13, 855–861 (2000). https://doi.org/10.1023/A:1007867710512
Issue Date:
DOI: https://doi.org/10.1023/A:1007867710512