Structures and electronic structures of potassium-doped C60 monolayers
Hyoung Joon Choi
Korea Institute for Advanced Study, Seoul 130-722, Korea
We present first-principles calculation of structures and electronic structures of K3C60 monolayers on Ag (111) and (001) surfaces. In case of K3C60 monolayers on the Ag (111) surface, we consider C60 molecules put in a hexagonal array with the lattice constant of 10.02 Å, and calculate the total energy and the energy-band dispersion for various molecular orientations. We find a C60 molecular orientation whose total energy is very close to the minimum and its LUMO-derived band dispersion has the important features observed by a high-resolution angle-resolve photoelectron spectroscopy (ARPES). The calculated bandwidth, however, is still substantially larger than the measured one, suggesting a renormalization effect in real samples. In case of K3C60 monolayers on the Ag (001) surface, we study the c(6*4) structure with the inter-fullerene distances of 10.42 and 11.57 Å, and obtain very different LUMO-derived energy-band dispersions. We also study spatial distribution of potassium atoms in C60 monolayers and its effect on the C60-derived energy-band dispersions.
1. W. L. Yang, V. Brouet, X. J. Zhou, H. J. Choi, S. G. Louie, M. L. Cohen, S. A. Kellar, P. V. Bogdanov, A. Lanzara, A. Goldoni, F. Parmigiani, Z. Hussain, Z.-X. Shen, Science 300, 303 (2003).
2. V. Brouet, W. L. Yang, X. J. Zhou, H. J. Choi, S. G. Louie, M. L. Cohen, A. Goldoni, F. Parmigiani, Z. Hussain, Z.-X. Shen, Phys. Rev. Lett. 93, 197601 (2004).
3. Y.-M. Byun, H. J. Choi, S. G. Louie, M. L. Cohen (to be published).