Electronic structure of alkali metal dopedC60derived from thermoelectric power measurements

The thermoelectric power of K- and Rb-doped ${\mathrm{C}}_{60}$ superconductors prepared from single crystals grown from a ${\mathrm{CS}}_2$ solution is reported. Nearly linear temperature dependences of the thermoelectric power with negative sign are observed above the superconducting transition temperatures for both materials. From the slope of the linear correlation, the ratio of the density of states at the Fermi energy, ${\mathit{N}}^{\mathrm{Rb}}$(${\mathit{E}}_{\mathit{F}}$)/${\mathit{N}}^{\mathrm{K}}$(${\mathit{E}}_{\mathit{F}}$), is estimated to be 1.5–1.8.