Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scanning Tunneling Spectroscopy of Subsurface Ag and Ge Impurities in
  Copper   We investigate single Ge and Ag impurities buried below a Cu(100) surface
using low temperature scanning tunneling microscopy. The interference patterns
in the local density of states are surface scattering signatures of the bulk
impurities, which result from 3D Friedel oscillations and the electron focusing
effect. Comparing the isoelectronic d scatterer Ag and the sp scatterer Ge
allows to distinguish contributions from impurity scattering and the host.
Energy-independent effective scattering phase shifts are extracted using a
plane wave tight-binding model and reveal similar values for both species. A
comparison with ab-initio calculations suggests incoherent sp scattering
processes at the Ge impurity. As both scatterers are spectrally homogeneous,
scanning tunneling spectroscopy of the interference patterns yields real-space
signatures of the bulk electronic structure. We find a kink around zero bias
for both species that we assign to a renormalization of the band structure due
to many-body effects, which can be described with a Debye self-energy and a
surprisingly high electron-phonon coupling parameter $\lambda$. We propose that
this might originate from bulk propagation in the vicinity of the surface.

22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an