From Slater to Mott–Heisenberg physics: the antiferromagnetic phase of the Hubbard model

We study the optical conductivity of the one-band Hubbard model in the Néel state at half filling at T = 0 using the dynamical mean-field theory. For small values of the Coulomb parameter clear signatures of a Slater insulator expected from a weak-coupling theory are found, while the strongly correlated system can be well described in terms of a Mott–Heisenberg picture. However, in contrast to the paramagnet, we do not find any evidence for a transition between these two limiting cases but rather a smooth crossover as a function of the Coulomb interaction.