Single-particle spectral function of the Hubbard chain: frustration induced

Abstract

The one-electron spectral function of a frustrated Hubbard chain is computed by making use of the cluster perturbation theory. The spectral weight we found turns out to be strongly dependent on the frustrating next-nearest-neighbor hopping t . A frustration induced pseudogap arises when the system evolves from a gapful Mott insulator to a gapless conductor for an intermediate value of the frustration parameter |t |. Furthermore, the opening of a pseudogap in the density of states already in the metallic side leads to a continuous opening of the true gap in the insulator. For the hole-doped case, the pseudogap is pinned at the Fermi energy, while the Mott gap is shifted in energy with increasing Hubbard interaction U . The separation of the pseudogap and Mott gap in the hole-doped system demonstrates the validity of the existence of a pseudogap.

Electron-correlation-induced band renormalization and Mott transition in Ca1−xSrxVO3

“…[5,6] When the divalent ion Sr 2+ substitutes the trivalent ion La 3+ , not only the crystal structure but also the filling electrons are modified, which leads to a complicated system. According to the Hubbard model, [2,7,8] MIT can also be controlled by varying the relative magnitudes of the on-site Coulomb repulsion U and the bandwidth W . Therefore, the second type of MIT is bandwidth-controlled MIT, e.g., V 2 O 3 [9] and Ca 1−x Sr x VO 3 , [10−16] in which the filling electrons do not change, because both Sr 2+ and Ca 2+ are divalent ions.…”