Mott Transition in the Two-Dimensional Hubbard Model

Spectral properties of the two-dimensional Hubbard model near the Mott transition are investigated by using cluster perturbation theory. The Mott transition is characterized by freezing of the charge degrees of freedom in a single-particle excitation that leads continuously to the magnetic excitation of the Mott insulator. Various anomalous spectral features observed in high-temperature superconductors are explained in a unified manner as properties near the Mott transition.