Pressure-induced anomalies in the c -axis resistivity of potassium—intercalated graphite

Sharp anomalies are observed in the 300-K pressure-dependent c-axis resistance of stage 1-4 potassium---intercalated graphite. Extrapolating from previous x-ray-diffraction results, we speculate that the anomalies are dominated by transitions to higher pure stage with denser K packing, and that mixed-stage behavior accounts for precursor effects which we observe at pressures below the anomalies.