Edward Linscott - Correcting the failings of DFT: DFT+U, Koopmans spectral functionals, and DMFT

Quantum Fluids in Isolation virtual seminar on Dec. 10th, 2020.

Sign up for future email notifications here:

Dr. Edward Linscott, Ecole polytechnique federale de Lausanne

Abstract:

Density functional theory (DFT) is a popular method for electronic-structure calculations. But while Kohn-Sham eigenvalues can loosely mirror experimental quasiparticle energies, there is formally no connection between the two (except for the HOMO in exact DFT). Furthermore, the presence of self-interaction errors in semi-local DFT can make those eigenvalues an even poorer proxy for quasiparticle energies [1].

This talk will discuss three different methods for addressing these failings of DFT. The first, DFT+U, is a method commonly applied to ”strongly correlated” materials such as transition metal oxides [2]. The second, Koopmans spectral functionals, is an efficient approach for recovering spectral properties [3-5]. Finally, I will discuss dynamical mean field theory, with a particular focus on its application to metalloproteins [6-7]. For each of these methods I will present some calculations on real systems in order to demonstrate their strengths and shortcomings.

[1] Cohen et al., Science, 321, 792 (2008); [2] Linscott et al., Phys. Rev. B, 98, 235157 (2018); [3] Borghi et al., Phys. Rev. B 90, 075135 (2014); [4] Nguyen et al., Phys. Rev. X, 8, 021051 (2018); [5] Colonna et al., JCTC, 15, 1905 (2019); [6] Linscott et al, JCTC, 16, 4899 (2020); [7] al-Badri, Linscott, et al., Comm. Phys., 3 (2020)