Dresden 2020 – wissenschaftliches Programm
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MA 15.2: Vortrag
Montag, 16. März 2020, 15:15–15:30, HSZ 403
Spin-polarized transport in anti-ferromagnetic RuO2 — •Kyo-Hoon Ahn1, Atsushi Hariki1, Kwan-Woo Lee2,3, and Jan Kuneš1,4 — 1Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria — 2Division of Display and Semiconductor Physics, Korea University, Sejong 30019, Korea — 3Department of Applied Physics, Graduate School, Korea University, Sejong 30019, Korea — 4Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Praha 8, Czechia
We will present the origin of antiferromagnetism (AFM) in RuO2 using two approaches of static Hartree-Fock and density functional + dynamical mean-field theory. Since the ordering of two anti-parallel Ru sites does not change the translational symmetry, the AFM electronic structure is spin-polarized which is unique among commom antiferromagnets. In the Fermi surfaces the two spin channels are π/2-rotated to each other, classified as a spin-triplet d-wave Pomeranchuk instability. Comparing the energy difference of paramagnetic (PM) and AFM for the entire Brillouin zone (BZ), we found a hot spot at the point K2 on the PM Fermi surface, where nodal-lines meets the BZ edge as well as the Ru1 and Ru2 characters touch each other. By constructing a model Hamiltonian for the K2 point, we show that the nodal-lines close to the Fermi level are split by the applied staggered potential, and this is the origin of the AFM instability.  Ahn et al., Phys. Rev. B 99, 184432 (2019).