Dual Fermion Approach to Susceptibility of Correlated Lattice Fermions

Date
Authors
Brener, S.
Hafermann, H.
Rubtsov, A. N.
Katsnelson, M. I.
Lichtenstein, A. I.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
In this paper, we show how the two-particle Green function (2PGF) can be obtained within the framework of the Dual Fermion approach. This facilitates the calculation of the susceptibility in strongly correlated systems where long-ranged non-local correlations cannot be neglected. We formulate the Bethe-Salpeter equations for the full vertex in the particle-particle and particle-hole channels and introduce an approximation for practical calculations. The scheme is applied to the two-dimensional Hubbard model at half filling. The spin-spin susceptibility is found to strongly increase for the wavevector $\vc{q}=(\pi,\pi)$, indicating the antiferromagnetic instability. We find a suppression of the critical temperature compared to the mean-field result due to the incorporation of the non-local spin-fluctuations.
Comment: 10 pages, 5 figures; substantially extended results section compared to version 1
Keywords
Condensed Matter - Strongly Correlated Electrons
Citation
Collections