INVESTIGADORES
VILDOSOLA Veronica Laura
artículos
Título:
2. Dynamical Mean-Field Theory within an Augmented Plane-Wave Framework: Assessing Electronic Correlations in the Iron Pnictide LaFeAsO
Autor/es:
MARKUS AICHHORN; LEONID POUROVSKII; VERONICA VILDOSOLA; MICHEL FERRERO; OLIVIER PARCOLLET; TAKASHI MIYAKE; ANTOINE GEORGES; SILKE BIERMANN
Revista:
PHYSICAL REVIEW B
Editorial:
AMER PHYSICAL SOC
Referencias:
Año: 2009 vol. 80 p. 85101 - 85115
ISSN:
1098-0121
Resumen:
We present
an approach that combines the local-density approximation (LDA) and the
dynamical mean-field theory (DMFT) in the framework of the
full-potential linear augmented plane-wave method. Wannier-type
functions for the correlated shell are constructed by projecting local
orbitals onto a set of Bloch eigenstates located within a certain
energy window. The screened Coulomb interaction and Hunds coupling are
calculated from a first-principles constrained random-phase
approximation scheme. We apply this LDA+DMFT
implementation, in conjunction with a continuous-time quantum Monte
Carlo algorithm, to the study of electronic correlations in LaFeAsO.
Our findings support the physical picture of a metal with intermediate
correlations. The average value of the mass renormalization of the Fe 3d
bands is about 1.6, in reasonable agreement with the picture inferred
from photoemission experiments. The discrepancies between different LDA+DMFT
calculations (all technically correct) which have been reported in the
literature are shown to have two causes: (i) the specific value of the
interaction parameters used in these calculations and (ii) the degree
of localization of the Wannier orbitals chosen to represent the Fe 3d
states, to which many-body terms are applied. The latter is a
fundamental issue in the application of many-body calculations, such as
DMFT, in a realistic setting. We provide strong evidence that the DMFT
approximation is more accurate and more straightforward to implement
when well-localized orbitals are constructed from a large energy window
encompassing Fe-3d, As-4p, and O-2p
and point out several difficulties associated with the use of extended
Wannier functions associated with the low-energy iron bands. Some of
these issues have important physical consequences regarding, in
particular, the sensitivity to the Hunds coupling.