Role of alkali atoms in A4C60.

Gunnarsson O., Erwin S.C., Koch E., Martin R.M.

Max-Planck-Institut für Festkörperforschung, Stuttgart;
Complex Systems Theory Branch, Naval Research Laboratory, Washington, D.C. 20375-5000

We show that hopping via 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 we present tightbinding and ab initio bandstructure calculations to support our conclusions.

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Physical Review B, 57 2159-62, 1998.

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