  Two-dimensional (2D) electrides are a new concept material in which anionic
electrons are confined in the interlayer space between positively charged
layers. We have performed angle-resolved photoemission spectroscopy
measurements on Y$_2$C, which is a possible 2D electride, in order to verify
the formation of 2D electride states in Y$_2$C. We clearly observe the
existence of semimetallic "electride bands" near the Fermi level, as predicted
by ${ab}$ ${initio}$ calculations, conclusively demonstrating that Y$_2$C is a
quasi-2D electride with electride bands derived from interlayer anionic
electrons.
