On the correllation effect in Peierls-Hubbard chains

TL;DR

This paper reevaluates the dimerization, charge, and spin gaps in a half-filled Peierls-Hubbard chain using the incremental expansion technique, revealing significant discrepancies with previous bosonization and renormalization group results, especially for the charge gap.

Contribution

It introduces the incremental expansion technique to study Peierls-Hubbard chains, providing more accurate numerical results and clarifying the limitations of previous methods.

Findings

Numerical results conflict with previous bosonization and RG results.

Charge gap estimates differ significantly from earlier studies.

Method is more reliable in strongly correlated regimes.

Abstract

We reexamine the dimerization, the charge and the spin gaps of a half-filled Peierls-Hubbard chain by means of the incremental expansion technique. Our numerical findings are in significant quantitative conflict with recently obtained results by M. Sugiura and Y. Suzumura [J. Phys. Soc. Jpn. v. 71 (2002) 697] based on a bosonization and a renormalization group method, especially with respect to the charge gap. Their approach seems to be valid only in the weakly correlated case.