Optical investigation of 6A1g(6S)→4T2g (4D) absorption band in magnetic MnF2 and RbMnF3 compounds

Spin-orbit excitations and electronic structure of the putative Kitaev magnetα−RuCl3

“…However, this is not the case, as spin is not a conserved quantity in RuCl 3 due to SOC. Our measurements show that the spectral weight SW = 0.87 eV 0.1 eV ω 2 (ω)dω of the A 1 -A 3 features in RuCl 3 is 1.5 × 10 −2 eV 2 at 10 K. As a comparison, the spin-forbidden 6 A 1g → 4 A 1g , 4 E g and 6 A 1g → 4 T 2g transitions in MnF 2 have spectral weights in the 10 −5 eV 2 range, more than two orders of magnitude lower [53,54] selection rule due to the spin-orbit coupled nature of the Ru d states in RuCl 3 . In fact, the SW of the orbital excitations in RuCl 3 is comparable to the values observed for spin-allowed transitions in 3d transition metal compounds, whose spectral weights typically fall in the 10 −3 to 10 −2 eV 2 range [39, 55, 56][57] A last consistency check of our assignment concerns the different orbital character of A 0 compared to A 1 -A 3 .…”