Extracting a more realistic pseudopotential for aluminum, lead, niobium and tantalum from superconductor electron tunnelling spectroscopy data

Electron tunnelling spectroscopy when first developed was used to extract the electron-phonon spectral density, α2F(ν), from superconductive metals. Here, on revisiting the topic, we show that it further allows the direct extraction of more realistic pseudopotentials for such metals. The pseudopotential so extracted has a range of surprising but physically reasonable properties and regenerates the experimentally derived α2F(ν) accurately. Freed from most of its long-standing uncertainties, this pseudopotential may find wide application.