  Within the last decade powerful methods have been developed to study surfaces
using bright low-energy positron beams. These novel analysis tools exploit the
unique properties of positron interaction with surfaces, which comprise the
absence of exchange interaction, repulsive crystal potential and positron
trapping in delocalized surface states at low energies. By applying reflection
high-energy positron diffraction (RHEPD) one can benefit from the phenomenon of
total reflection below a critical angle that is not present in electron surface
diffraction. Therefore, RHEPD allows the determination of the atom positions of
(reconstructed) surfaces with outstanding accuracy. The main advantages of
positron annihilation induced Auger-electron spectroscopy (PAES) are the
missing secondary electron background in the energy region of Auger-transitions
and its topmost layer sensitivity for elemental analysis. In order to enable
the investigation of the electron polarization at surfaces low-energy
spin-polarized positrons are used to probe the outermost electrons of the
surface. Furthermore, in fundamental research the preparation of well defined
surfaces tailored for the production of bound leptonic systems plays an
outstanding role. In this report, it is envisaged to cover both, the
fundamental aspects of positron surface interaction and the present status of
surface studies using modern positron beam techniques.
