  We report experimental evidence for charged boson states in a solid without
Cooper pairing, based on attaching two free carriers to an exciton in a
semiconducting system. Theoretical calculations show that this type of complex
is stable in bilayer systems next to a parallel metal layer. Our experimental
measurements on structures made using two different materials show a new
spectral line at the predicted energy, if and only if all the required
conditions for this complex are fulfilled, including a parallel metal layer
that significantly screens the repulsive interaction between the like-charge
carriers, and with the predicted dependence on the distance to the metal layer.
This suggests a new path for pursuing room temperature superconductivity
without Cooper pairing.
