Local Spectral Inversion and Bosonic Fine Structure Extraction via Superconducting Scanning Tunneling Spectroscopy
arXiv:1211.2244
Abstract
We perform the scanning tunneling spectroscopy based superconductor-vacuum-superconductor analogue to the seminal McMillan and Rowell superconductor-insulator-superconductor device study of phonons in the archetypal elemental superconductor Pb [W. L. McMillan and J. M. Rowell, Phys. Rev. Lett. 14, 108 (1965)]. We invert this spectroscopic data utilizing strong-coupling Eliashberg theory to obtain a local α^2F(ω) and find broad underlying agreement with the pioneering results, highlighted by previously unobserved electron-hole asymmetries and new fine structure which we discuss in terms of both conventional and unconventional superconducting bosonics.