  We present a computationally efficient method to obtain the spectral function
of bulk systems in the framework of steady-state density functional theory
(i-DFT) using an idealized Scanning Tunneling Microscope (STM) setup. We
calculate the current through the STM tip and then extract the spectral
function from the finite-bias differential conductance. The fictitious
non-interacting system of i-DFT features an exchange-correlation (xc)
contribution to the bias which guarantees the same current as in the true
interacting system. Exact properties of the xc bias are established using
Fermi-liquid theory and subsequently implemented to construct approximations
for the Hubbard model. We show for two different lattice structures that the
metal-insulator transition is captured by i-DFT.
