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Phase Diagram Of The One-Dimensional Hubbard-Holstein Model At Half And Quarter Filling, Rahul Hardikar, R. T. Clay
Phase Diagram Of The One-Dimensional Hubbard-Holstein Model At Half And Quarter Filling, Rahul Hardikar, R. T. Clay
Scholarship and Professional Work - LAS
The Hubbard-Holstein model is one of the simplest to incorporate both electron-electron and electron-phonon interactions. In one dimension at half filling, the Holstein electron-phonon coupling promotes on-site pairs of electrons and a Peierls charge-density wave, while the Hubbard on-site Coulomb repulsion U promotes antiferromagnetic correlations and a Mott insulating state. Recent numerical studies have found a possible third intermediate phase between Peierls and Mott states. From direct calculations of charge and spin susceptibilities, we show that (i) as the electron-phonon coupling is increased, first a spin gap opens, followed by the Peierls transition. Between these two transitions, the metallic intermediate …
Intermediate Phase Of The One Dimensional Half-Filled Hubbard-Holstein Model, R. T. Clay, Rahul Hardikar
Intermediate Phase Of The One Dimensional Half-Filled Hubbard-Holstein Model, R. T. Clay, Rahul Hardikar
Scholarship and Professional Work - LAS
We present a numerical study of the Hubbard-Holstein model in one dimension at half filling, including finite-frequency quantum phonons. At half filling, the effects of the electron-phonon and electron-electron interactions compete with the Holstein phonon coupling acting as an effective negative Hubbard on-site interaction U that promotes on-site electron pairs and a Peierls charge-density wave state. Most previous work on this model has assumed that only Peierls or Mott phases are possible at half filling. However, there has been speculation that a third metallic phase exists between the Peierls and Mott phases. We confirm the intermediate phase, and show that …