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, α 2 F(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 α 2 F(ν) accurately. Freed from most of its long-standing uncertainties, this pseudopotential may find wide application.