Dynamical Mean-Field Theory + Numerical Renormalization Group Study of Strongly Correlated Systems with Spin-Orbit Coupling

Gianni Del Bimbo LMU

28.02.2020

In the context of strongly correlated systems, the new paradigm of Hund metals has recently emerged. Over the past decade these systems, for which the correlations are driven by Hund coupling rather than Coulomb repulsion, have been intensively studied employing a three-band Hubbard-Kanamori model [1]. Examples of materials are ruthenates and iron-based superconductors. Although spin-orbit coupling (SOC) has been commonly neglected, its role has recently been reconsidered and has attracted much interest [2,3]. Yet the effects of SOC in strongly correlated metals are not well understood. In my thesis, using single-site Dynamical Mean-Field Theory (DMFT) [4] with Numerical Renormalization Group (NRG) as impurity solver [5], I studied how the T=0 paramagnetic phase of Hund metals is changed by SOC. In the talk, I will present how, for example, SOC affects spectral functions and susceptibilities, and discuss its influence on correlations.

[1] A. Georges, L. de' Medici and J. Mravlje. Strong Correlations from Hund's Coupling. Annu. Rev. Condens. Matter Phys. 4 (2013).
[2] A. Horvat, R. Žitko and J. Mravlje. Spin-orbit coupling in three-orbital Kanamori impurity model and its relevance for transition-metal oxides. Phys. Rev. B. 96 (2017).
[3] R. Triebl, G.J. Kraberger, J. Mravlje and M. Aichhorn. Spin-orbit coupling and correlations in three-orbital systems. Phys. Rev. B 98 (2018).
[4] A. Georges, G. Kotliar, W. Krauth and M.J. Rozenberg. Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions. Rev. Mod. Phys. 68 (1996).
[5] R. Bulla, T.A. Costi, and T. Pruschke. Numerical renormalization group method for quantum impurity systems. Rev. Mod. Phys. 80 (2008).