Probing many-body scattering in Cu(111) via FT-STS: Understanding local perturbations from the collective signatures of a 2D electron gas

Surface states of close-packed noble metals provide one of the simplest scenarios for studying many-body scattering in two dimensions, turning them into a relatively simple platform to test novel spectroscopic techniques. In this talk I will present a study of the Cu(111) surface state with high-resolution Fourier Transform Scanning Tunnelling Spectroscopy (FT-STS), and for the first time demonstrate that the QPI lineshape can be quantitatively fit using many-body effects within the T-matrix formalism. Specifically, the self-energies and the scattering phase-shifts are quantified for both the occupied and unoccupied states, further expanding the capabilities of FT-STS beyond its conventional application as merely a probe of the energy dispersion in scattering space.