Electronic anomalies in dilute synthetic metals

Extended families of synthetic p metals can be prepared by controlled intercalation of electron acceptor molecules between the carbon hexagon networks of well oriented graphite. Resistivities and Hall coefficients have been determined down to 1.8 K for graphite bisulphates and (to a more limited extent) for graphite perchlorates. For many of these dilute synthetic metals, peak anomalies are found in Hall effects at around 20 K . These are discussed in relation to possible changes in the structure of the intercalate layers with temperature.