  A three dimensional mapping of the Fermi Surface (FS) of the rare-earth
compound ErGa3 was determined via measurements of the angular correlation of
the electron-positron annihilation radiation. The topology of the electronlike
FS does show nesting properties which are consistent with the modulated
antiferromagnetic structure of the system. We determine the density of states
at the Fermi energy N(EF) and the electronic contribution to the gamma constant
to be N(EF)=16 states/Ryd/cell and gamma=2.7 (mJ/mole K^2), respectively.
Densities rho(k) of ErGa3 and TmGa3 in the kz=0 and kz=pi/a plane of the
Brillouin zone reconstructed from 2D ACAR data. The arrow highlights the
nesting feature attributed to TmGa3 and ErGa3 (left and right sides,
respectivelty).
