Anomalous metallicity and electronic phase separation in the CsC60 polymerized fulleride

Abstract

133Cs and 13C-NMR have been used to study the electronic properties of the polymerized phase of CsC60 at ambient and under hydrostatic pressure. The salient result of this study is the finding of fluctuations in the local field at 133Cs site which are independent of the applied pressure and due to thermally activated changes in the local electronic environment of 133Cs nuclei. We establish that the phase separation between magnetic and nonmagnetic domains observed in the low temperature state at ambient pressure is the result of a slowing down of these fluctuations likely related to polaronic charge excitations on the polymers.