Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 44: Correlated Electrons: Method Development
TT 44.2: Talk
Wednesday, April 3, 2019, 15:15–15:30, H7
Self-Consistent Ladder Dynamical Vertex Approximation — •Josef Kaufmann1, Anna Kauch1, Oleg Janson1,2, and Karsten Held1 — 1Institute for Solid States Physics, TU Wien — 2IFW Institute for Theoretical Solid State Physics, Dresden
The dynamical vertex approximation (DΓA) is a
diagrammatic extension [1] of the dynamical mean-field theory (DMFT).
In the so-called ladder-DΓA, one treats the
irreducible vertex in the particle-hole channel as completely
local and builds nonlocal ladder diagrams from it,
which are then used as corrections to the DMFT self-energy.
The local vertex is extracted from two-particle Green’s functions,
calculated by using continuous-time quantum Monte Carlo
for an effective Anderson impurity model [2,3].
Traditionally, self-consistency has been mimicked by
a so-called λ-correction.
In this talk, we go a considerable step beyond and present
a self-consistent formulation and solution of
the DΓA equations, naturally fulfilling
physical constraints, such as the asymptotics of the self-energy.
The applicability is demonstrated in calculations for the
Hubbard model on a square lattice and on a (geometrically
frustrated) Kagome lattice.
G. Rohringer et al., Rev. Mod. Phys. 90, 025003 (2018)
P. Gunacker et al., Phys. Rev. B 92, 155102 (2015)
J. Kaufmann et al., Phys. Rev. B 96, 035114 (2017)