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The field of first principles electronic structure calculations for strongly correlated materials
has witnessed tremendous progress in recent years due to the development of a very powerful
finite temperature technique combining density functional theory (DFT) and dynamical mean
field theory (DMFT), popularly called the “DFT+DMFT” method. In this talk, I will focus on
analysing the electron correlation effects on the properties of two interesting classes of materials
using this newly developed technique.
In the first part of my talk, I will highlight the failure of the DFT and DFT+Hubbard U
approaches on explaining the measured, high values of the axial and transverse anisotropy
parameters of a single Fe atom supported on a Cu 2 N surface, which serves as a prototype in this
class of magnetic nano- or subnano-systems. In particular, I will discuss the importance of
treating fluctuating magnetic moments and understanding its spin excitation spectra (as
measured by STM) through a realistic many-body treatment.
In the second part of my talk, I will outline a complete many-body theoretical framework for
the analysis of the valence band spectrum of complex transition metal oxides taking the
example of NiO which is the most enigmatic oxide with strong correlation effects, and often
serves as the system of choice when new experimental and theoretical methods are
benchmarked. In this context, I will also discuss the significance of non-local correlations, the
first principle estimation of dynamically screened Hubbard interaction (“U”) and the
importance of incorporating them into the DMFT-based description of correlated materials.
Relevant References:
Cyrus et al, Science 317, 1199 (2007)
Shick et al, PRB 79, 172409 (2009)
Panda et al, PRB 93, 140101 (R) (2016)
Thunström et al, PRL 109, 186401 (2012)
Panda et al, PRB 93, 235138 (2016)
Vaugier et al, PRB 86, 165105 (2012)
Panda et al, arXiv : 1612.07571 |