# Dresden 2014 – wissenschaftliches Programm

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# HL: Fachverband Halbleiterphysik

## HL 93: Frontiers of electronic structure theory - Non-equilibrium phenomena at the nano-scale VI (organized by O)

### HL 93.10: Vortrag

### Donnerstag, 3. April 2014, 13:00–13:15, TRE Ma

**Self-consistent dynamical embedding in real space** — •Wael Chibani^{1}, Xinguo Ren^{1,2}, Patrick Rinke^{1}, and Matthias Scheffler^{1} — ^{1}*Fritz Haber Institute of the Max Planck Society, Berlin, Germany* — ^{2}*Key Laboratory of Quantum Information, USTC, Hefei, China*

Density-functional theory with its local-density (LDA) and generalized gradient approximations
(GGA) is known to fail for localized states.
To extend *ab initio* approaches to this domain, we have devised an embedding scheme that facilitates
the treatment of the physically important part of a system with electronic structure methods, that are computationally too
expensive for periodic systems, whereas the rest of the periodic system is treated with
computationally less demanding approaches, i.e. LDA/GGA, in a self-consistent manner.
Our scheme is based on the concept of dynamical mean-field theory (DMFT) [1].
However, in contrast to the original DMFT formulation for correlated
model Hamiltonians, we consider here the unit cell as embedded cluster in an *ab initio* way,
that includes all electronic degrees of freedom.
The performance of our scheme is demonstrated by treating the embedded region with hybrid functionals for simple bulk systems, e.g. Si or NiO.
The total energy and the density of states converge rapidly with respect to the computational parameters and approach their bulk limit with increasing cluster size.
By treating the embedded region with *GW* we were able to improve the band gap using only a small cluster. The effect of self-consistency in *GW* for the embedded region will also be addressed.
[1] A. Georges *et al.*, Rev. Mod. Phys. **68**,14 (2006)