# Dresden 2014 – wissenschaftliches Programm

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# HL: Fachverband Halbleiterphysik

## HL 99: Electronic structure theory

### HL 99.2: Vortrag

### Donnerstag, 3. April 2014, 15:15–15:30, POT 151

**Predictive ***GW*** calculations with pseudopotentials and plane-waves** — •Jiri Klimes and Georg Kresse — Faculty of Physics, University of Vienna, Sensengasse 8/12, A-1090 Wien, Austria

The *GW* approximation is the standard approach to obtain quasi-particle (QP)
energies in solid state physics.
Despite its wide use, the agreement between values obtained by different
implementations is often unsatisfactory, even for the simplest case of *G*_{0}*W*_{0}@LDA.
This is often attributed to the use of pseudopotentials or to the limited size
of local basis sets in all-electron codes.
Moreover, little attention is usually paid to obtain results that are converged with respect
to the size of the basis sets for orbitals and for the response function.
Here we derive an analytic formula for the contribution of
unoccupied states with high kinetic energies to the QP corrections.
This clearly shows the necessity to converge with the number and basis set size for unoccupied
states as well as with the basis set size for the response function.
It also points to a problem in the current projector-augmented-wave (PAW) *GW* calculations
that originates from the incompleteness of the on-site basis set of partial waves.
We show that this issue can be avoided by using norm-conserving PAW partial-waves in the *GW* calculations.
Our results are then in a very good agreement with the values obtained using
all-electron FLAPW+lo method, even for the problematic case of ZnO [1].

[1] C. Friedrich, M. C. Müller, and S. Blügel, PRB **83**, 081101(R) (2011); **84**, 039906 (2011).