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UBC Theses and Dissertations

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


Surface states of close-packed noble metals form an approximate two-dimensional electron gas whose many-body signatures can be locally probed using a scanning tunneling microscope (STM). In this work I present a study of the Cu(111) surface state with high-resolution Fourier Transform Scanning Tunneling Spectroscopy (FT-STS), and for the first time demonstrate that the energy dispersion and quasi-particle lifetime of the surface states can be accurately quantified in both the occupied and unoccupied states. The scat-tering phase-shift imposed by defect potentials is then extracted in Fourier space, which is consistent with previous real space analyses. This result is later used in the T-matrix simulation of the density of states that gives an accurate description of our data. Finally, I report that in dilute Co/Cu(111) where the absence of time-reversal symmetry allows for spin-flip scattering, spin-conserving scattering dominates the FT-STS signal.

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