Important role of alkali atoms in A₄C₆₀

O. Gunnarsson (a), S.C. Erwin (b), E. Koch (c) and R.M. Martin (c)
(a) Max-Planck-Institut für Festkörperforschung, Stuttgart

(b) Complex Systems Theory Branch, Naval Research Laboratory, Washington, D.C. 20375-5000

(c) Department of Physics, University of Illinois, Urbana, Illinois 6180

We show that hopping via the alkali atoms plays an important role for the t1u band of A4C60 (A=K, Rb), in strong contrast to A3C60. Thus the t1u band is broadened by more than 40 % by the presence of the alkali atoms. The difference between A4C60 and A3C60 is in particular due to the less symmetric location of the alkali atoms in A4C60.

Phys. Rev. B 57, 2159 (1998).

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