Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 3: Correlated Electrons: Frustrated Magnets - Pyrochlore Systems and Iridates

TT 3.5: Vortrag

Montag, 7. März 2016, 10:30–10:45, H20

Determination of the spin Hamiltonian in the pyrochlore Lu₂V₂O₇ — •Kira Riedl¹, Harald O. Jeschke¹, Michel J.P. Gingras^2,3,4, and Roser Valenti¹ — ¹Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany — ²Department of Physics and Astronomy, University of Waterloo, Ontario, N2L 3G1, Canada — ³Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5, Canada — ⁴Canadian Institute for Advanced Research, 180 Dundas Street West, Suite 1400, Toronto, ON, M5G 1Z8, Canada

In the pyrochlore Lu₂V₂O₇ the vanadium ions form corner-sharing spin 1/2 tetrahedra. In order to find the corresponding spin Hamiltonian which captures the essential physics of the investigated compound we performed a tight-binding fit on the vanadium d orbitals using density functional theory. Since there is evidence that the Dzyaloshinskii-Moriya interaction (DMI) is important in this system, we considered spin-orbit coupling effects within our calculations.

A fitting procedure to the relativistic band structure enabled us to determine the strength of the spin-orbit coupling. In a second step, we calculated the energy parameters in the spin Hamitonian with the method of exact diagonalization and projection on low energy states. We were therefore able to evaluate the Heisenberg exchange, the DMI, and the symmetric tensor, only using ab initio information and reasonable values for the Hubbard interaction as well as for the Hund’s coupling. Comparison with recent experimental results will be discussed.