We formulate a Time-Dependent Density-Functional Theory+ Dynamical Mean-Field Theory (TDDFT+DMFT) approach to study the non-equilibrium properties of materials with strong electron-electron interactions. In the proposed algorithm, one calculates the exchange-correlation (XC) potential by solving the Schlueter-Sham equation with the electron self-energy obtained within the many-body DMFT approach. In DMFT, the effects of electron-electron interaction are successfully taken into account by mapping the problem on an effective single-site (impurity) problem. As the next step, one solves the non- equilibrium problem by using TDDFT with the DMFT XC potential. We apply the approach to study the femtosecond response of the antiferromagnetic insulator MnO to an ultrafast laser pulse perturbation. In particular, we analyze possible excited states in the system, including excitons, the dynamics of the excited electrons and the relaxation stages of the system. We compare our results with available experimental data[1] and demonstrate that the TDDFT+DMFT is capable to describe the relaxation stages of the system. Our results suggest that strong electron-electron interactions play an important role in the system response.
[1] J. Nishitani at al., Phys. Stat. Sol. C 13, 113 (2016).
Work supported in part by DOE Grant No. DOE-DE-FG02-07ER46354.
This is joint work with Volodymyr Turkowski (Univ. of Central Florida) and Talat S. Rahman (Univ. of Central Florida).
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