Charge ordering and correlation effects in the extended Hubbard model

Hanna Terletska, Tianran Chen, and Emanuel Gull
Phys. Rev. B 95, 115149 – Published 27 March 2017

Abstract

We study the half-filled extended Hubbard model on a two-dimensional square lattice using cluster dynamical mean-field theory on clusters of size 8–20. We show that the model exhibits metallic, Mott-insulating, and charge-ordered phases, and determine the location of the charge-ordering phase-transition line and the properties of the phases as a function of temperature, local interaction, and nearest-neighbor interaction. We find strong nonlocal correlations outside the charge-ordered phase and a pronounced screening effect in the vicinity of the phase transition, where nonlocal interactions push the system towards metallic behavior. In contrast, correlations in the charge-ordered phase are mostly local to the unit cell. Finally, we demonstrate how strong nonlocal electron-electron interactions can increase electron mobility by turning a charge-ordered insulator into a metal. We analyze finite-size effects and the convergence of our data to the thermodynamic limit. Control of all sources of errors allows us to assess the regime of applicability of simpler approximation schemes for systems with nonlocal interactions.

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  • Received 23 November 2016
  • Revised 7 March 2017

DOI:https://doi.org/10.1103/PhysRevB.95.115149

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Hanna Terletska1, Tianran Chen2, and Emanuel Gull1

  • 1Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
  • 2Department of Physics, West Chester University of Pennsylvania, West Chester, Pennsylvania 19383, USA

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Issue

Vol. 95, Iss. 11 — 15 March 2017

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