Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 28: Electronic Structure Theory: General I
O 28.11: Talk
Tuesday, March 13, 2018, 13:00–13:15, MA 141
Importance of spin-orbit and on-site Coulomb interactions on the electronic structure and lattice dynamics of thorium and actinium — •Lukas Kyvala and Dominik Legut — VSB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava, Czech Republic
We investigate electronic structure and lattice dynamics of thorium and actinium within density function theory. Recently, Actinium (Ac) shows excellent potential in radiotherapy and Thorium (Th) appears to be a suitable substitution for uranium in novel nuclear fuels. Therefore, we determined the effect of spin-orbit interaction (SOI) for the electronic, elastic, phonon and thermodynamic properties of number of Ac phases (hcp, bcc, fcc, and sc). Similarly, in the case of Th in addition to SOI we investigated also localized versus itinerant behavior of the f electrons. Therefore we applied so-called Hubbard parameter U in the range of 0.5-2 eV for the Th 5f electrons. Next, we calculated the elastic tensor by the linear-response method as implemented in VASP code to determine elastic constants (Cij). Subsequently, the criteria of stability based on Cij were evaluated. Subsequently, we calculated vibrational properties using the direct force-constant method as implemented in the PHONOPY code. Actinium phase transition is discussed within the quasi-harmonic approximation under temperature and pressure. Our calculated mechanical and thermodynamicl properties of Th are in good agreement with experimental data and for the Ac element serve as prediction. This work was supported by CSF grant No. 17-27790S and project No. CZ.02.1.01/0.0/0.0/16_013/0001791.