Abstract
Measurements of the resistivity of Nb-doped SrTiO3 show that the two highest LO modes couple most strongly to the conduction electrons. The conjecture that these polar modes are the dominant ones for superconductivity is confirmed by a remarkable correlation between the carrier-concentration dependence of the corresponding contributions to the resistivity and that of the superconducting transition temperature. Electron coupling to polar modes with energies above the Fermi level singles-out doped SrTiO3 among all other superconductors. © 1981.