Record Details

Title:
Beyond extended dynamical mean-field theory: Dual boson approach to the two-dimensional extended Hubbard model
Affiliation(s):
EuXFEL staff, Other
Author group:
Theory
Topic:
Scientific area:
Abstract:
The dual boson approach [Rubtsov, Katsnelson, and Lichtenstein, Ann. Phys. 327, 1320 (2012)] provides a means to construct a diagrammatic expansion around the extended dynamical mean-field theory (EDMFT). In this paper, we present the numerical implementation of the approach and apply it to the extended Hubbard model with nearest-neighbor interaction $V$. We calculate the EDMFT phase diagram and study the effect of diagrams beyond EDMFT on the transition to the charge-ordered phase. Including diagrammatic corrections to the EDMFT polarization shifts the EDMFT phase boundary to lower values of $V$. The approach interpolates between the random phase approximation in the weak coupling limit and EDMFT for strong coupling. Neglecting vertex corrections leads to results reminiscent of the EDMFT+$GW$ approximation. We, however, find significant deviations from the dual boson results already for small values of the interaction, emphasizing the crucial importance of fermion-boson vertex corrections.
Imprint:
American Physical Society, 2014
Journal Information:
Physical Review B, 90 (23), 235135 (2014)
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Language(s):
English
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