Pressure dependence of the electronic density of states and T-c in superconducting Rb3C60

The functional dependence of the superconducting transition temperature T-c on the electronic density of states N(E(f)) was determined for Rb3C60 by measuring the magnetic susceptibility under hydrostatic pressure to similar to 1 GPa in a commercial SQUID magnetometer. Both T-c and N(E(f)) decrease under pressure at the rates -31%/GPa and -14.5%/GPa, respectively, but lie above the corresponding values for K3C60 at the same lattice parameter. The present results are consistent with weak-coupling BCS theory with characteristic energy E(char)/k(B) approximate to 320-810 K.