Speakers: Giniyat Khaliullin (Max Planck Institute for Solid State Research, Stuttgart, Germany)
Place: Na Slovance, main lecture hall
Presented in English
Organisers:
Department of Condensed Matter Theory
Abstract:
After a general introduction to spin-orbital physics in transition metal compounds, I will focus on a special class of Mott insulators with the t42g electronic configuration, where spin-orbit coupling dictates a nonmagnetic ground state and the magnetic response is governed by gapped singlet-triplet excitations. The exchange interactions as well as crystalline electric fields may close the spin gap, resulting in a Bose condensation of spin-orbit excitons. In addition to usual magnons, a “Higgs” amplitude mode, most prominent near the quantum critical point, is expected. Upon electron doping, ferromagnetic correlations and an unconventional triplet superconductivity may emerge. These predictions [1,2] will be discussed in context of the recent experiments in ruthenium oxides [3].
[1] G. Khaliullin, Phys. Rev. Lett. 111, 197201 (2013).
[2] J. Chaloupka and G. Khaliullin, Phys. Rev. Lett. 116, 017203 (2016).
[3] A. Jain et al., arXiv: 1510.07011.
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