Steady-State Density Functional Theory for Correlated Quantum Transport and Spectral Functions

Steady-State Density Functional Theory (i-DFT) is a formalism to describe open quantum systems in nonequilibrium steady states. i-DFT is based on the one-to-one correspondence between the pair density and steady current and the pair local potential and applied voltage. The resulting Kohn-Sham system features two exchange-correlation (xc) potentials, a local xc potential and an xc contribution to the voltage. After revisiting the fundamentals of i-DFT we apply the formalism to correlated quantum dots in the Coulomb blockade regime. We show that the well-known discontinuity of the DFT xc potential at integer particle number bifurcates at finite currents. The i-DFT formalism can also be used to calculate bulk spectral functions. We present an approximation to the xc voltage suited to describe a paradigm in the field of strongly correlated electrons, i.e., the Mott metal-insulator transition.