  The significantly enhanced superconducting transition temperature ($T_c$) of
an FeSe monolayer on SrTiO$_3$(001) substrate has attracted extensive attention
in recent years. Here, based on first-principles electronic structure
calculations, we propose another candidate substrate LaO(001) for the epitaxial
growth of FeSe monolayer to realize superconductivity. Our calculations show
that for the optimal adsorption structure of FeSe monolayer on LaO(001), the
stripe antiferromagnetic state and the dimer antiferromagnetic state are almost
energetically degenerate, indicating the existence of strong magnetic
fluctuation that is beneficial to the appearance of superconductivity.
According to the Bader charge analysis, the calculated electron doping from the
LaO substrate to the FeSe monolayer is about 0.18 electrons per Fe atom, even
larger than that in case of FeSe/SrTiO$_3$(001). Since LaO was also reported to
be a superconductor with $T_c$ ~ 5 K, it may have a superconducting proximity
effect on the epitaxial FeSe film and vice versa. These results suggest that
LaO would be an interesting substrate to study the interface-related
superconductivity.
