Nature 351, 632 - 634 (20 June 1991); doi:10.1038/351632a0

Structure of single-phase superconducting K₃C₆₀

Peter W. Stephens^*, Laszlo Mihaly^*, Peter L. Lee^†, Robert L. Whetten^‡, Shiou-Mei Huang^‡, Richard Kaner^‡, François Deiderich^‡ & Karoly Holczer^‡

^*Department of Physics, State University of New York, Stony Brook, New York, 11794, USA
^‡New York State Institute on Superconductivity and Department of Chemistry, State University of New York, Buffalo, New York 14214, USA
^‡Department of Physics, Department of Chemistry and Biochemistry, and Solid State Science Center, University of California, Los Angeles, California 90024-1569, USA

RECENT reports^1–3 of superconductivity in alkali-metal-doped compounds of the icosahedral C₆₀ (buckminsterfullerene) molecule have attracted great experimental and theoretical interest. Superconductivity was originally discovered in samples prepared from gas–solid reactions¹, which made it impossible to determine the composition or structure of the superconducting phase. Holczer et al.⁴ demonstrated that potassium-doped C₆₀ has only a single stable superconducting phase, K₃C₆₀, with a transition temperature of 19.3 K. Improvements have since resulted in the preparation of 100% bulk superconductors³. Because of the absence of impurity phases, we have been able to perform accurate Rietveld analysis of X-ray diffraction data from the superconducting phase. Here we report our results for the crystal structure of K₃C₆₀, determining that this superconducting compound has a face-centred cubic structure with a well defined stoichiometry. These results should open the way to rigorous description of the normal and superconducting properties of this compound.

References

1.	Hebard, A. F. et al. Nature 350, 600−601 (1991). | Article | ISI | ChemPort |
2.	Holczer, K. et al. Science 252, 1154 (1991). | ChemPort |
3.	Rosseinsky, M. J. et al. Phys. Rev. Lett. 66, 2830−2832 (1991). | Article | PubMed | ChemPort |
4.	Sparn, G. et al. Science (submitted).
5.	Heiney, P. A. et al. Phys. Rev. Lett. 66, 2911−2914 (1991). | Article | PubMed | ChemPort |
6.	Zhou, O. et al. Nature 351, 462−464 (1991). | Article | ChemPort |
7.	Haddon, R. C. et al. Nature 350, 320−323 (1991). | Article | ISI | ChemPort |
8.	Bode, H. & Voss, E. Z. Anorg. Chem. 290, 1 (1957). | ChemPort |
9.	Rudorff, W. Advances in Inorganic Chemistry and Radiochemistry Vol. 1 (eds Emelius, H. J. & Sharp, A. G.) 225 (Academic Press, New York, 1959).
10.	Weaver, J. H. et al. Phys. Rev. Lett. 13, 1741−1744 (1991).
11.	Holczer, K. et al. Phys. Rev. Lett. (submitted).