  The two-dimensional nature of engineered transition-metal ultra-thin oxide
films offers a large playground of yet to be fully understood physics. Here, we
study pristine SrVO$_3$ monolayers that have recently been predicted to display
a variety of magnetic and orbital orders. Above all ordering temperatures, we
find that the associated non-local fluctuations lead to a momentum
differentiation in the self-energy, particularly in the scattering rate. In the
one-band 2D Hubbard model, momentum-selectivity on the Fermi surface
("$k=k_F$") is known to lead to pseudogap physics. Here instead, in the
multi-orbital case, we evidence a differentiation between momenta on the
occupied ("$k<k_F$") and the unoccupied side ("$k>k_F$") of the Fermi surface.
Our work, based on the dynamical vertex approximation, complements the
understanding of spectral signatures of non-local fluctuations, calls to
(re)examine other ultra-thin oxide films and interfaces with methods beyond
dynamical mean-field theory, and may point to correlation-enhanced
thermoelectric effects.
