Tunnel spectroscopy in superconductors under extreme conditions

Tunneling experiments on three systems, amorphous metals, La under pressure and Pd-H(D), have shown three possibilities to increase Tsub(c). An understanding of these phenomena can give new perspectives for the development of superconductors with higher transition temperatures. In all cases the lattice vibrations are shifted to lower frequencies more appropriate for superconductivity or newly created, the increase of the electron-phonon coupling probably playing an additional role. (orig./WBU)