Ab initio description of strongly-correlated materials: On the road to predictive power
Dr. Markus Aichhorn
Institute of Theoretical and Computational Physics, TU Graz
17:15 - 18:15 Tuesday 08 November 2016 TUG P2 Strongly-correlated materials show a variety of fascinating
properties, such as metal-insulator transitions, unconventional
superconductivity, or strongly enhanced magnetism. A common feature of
these fascinating materials is that potential and kinetic energy are
of similar strength and compete with each other, yielding fragile and
easy-to-perturbe ground states.
The theoretical description of these correlated compounds is
challenging, since both the itinerant motion of electrons and local
atomic-like physics has to be taken into account on the same footing.
This goal can be reached by combining density functional theory with
the dynamical mean-field theory [1], which allows for a continuous
interpolation between itinerant metals on the one hand, and
strongly-localized insulators on the other hand.
In this talk I will review recent advances in this field, using
selected topical examples. We will see how new developments of
numerical methods made it possible to address questions that we could
not answer a few years ago [2,3]. I will for instance discuss correlation
effects in iron-based superconductors, and highlight the effect of
Hund's rule coupling in these materials. We will furthermore identify
this coupling to be the reason for quite a number of unexpected
properties in 3d in 4d materials [4-6].
Although these examples will show that we have seen tremendous
progress in the ab initio description of correlated matter in recent
years, we are still not at the end of the road to true predictive
power. I will discuss the open issues in the context of one of our
current research focuses, which are spin-orbit coupled correlated
systems, such as iridium oxide crystals [7] and heterostructures.
[1] G. Kotliar et al., Rev. Mod. Phys. 78, 865, (2006).
[2] M. Aichhorn et al., Phys. Rev. B 80, 085101 (2009).
[3] M. Aichhorn et al., Comp. Phys. Comm. 204, 200 (2016).
[4] M. Aichhorn et al., Phys. Rev. B 82, 064504 (2010).
[5] J. Mravlje et al., Phys. Rev. Lett. 108, 197202 (2012).
[6] M. Zingl et al., Phys. Rev. B 94, 045130 (2016).
[7] C. Martins et al., Phys. Rev. Lett. 107, 266404 (2012).
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