Unraveling the Mn L₃-edge RIXS spectrum of lightly manganese-doped Sr₃Ru₂O₇

Yu-Cheng Shao^1*, Wei-Yang Chen², Shih-Wen Huang³, Yi Tseng³, Wenliang Zhang³, Eugenio Paris³, Teguh Citra Asmara³, Jenn-Min Lee⁴, Thorsten Schmitt³, Yi-De Chuang⁵, Byron Freelon⁶, Dao-Xin Yao², Trinanjan Datta^7,8

¹Experimental Facility Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
²School of Physics, Sun Yat-Sen University, Guangzhou, China
³Swiss Light Source, Paul Scherrer Institut, Villigen, Swaziland
⁴MAX IV Laboratory, Lund University, Lund, Sweden
⁵Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, USA
⁶Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, USA
⁷Department of Physics and Biophysics, Augusta University, Augusta, USA
⁸Kavli Institute for Theoretical Physics, University of California, Santa Barbara, USA

* Presenter:Yu-Cheng Shao, email:shao.yc@nsrrc.org.tw

A 10% Mn-doping on Ru site triggers the (¼, ¼, 0) antiferromagnetic (AF) order in Sr₃Ru₂O₇ compound, where the valence is Mn3+ in the 3d⁴ state. Here we perform resonant inelastic x-ray scattering (RIXS) experiment at the Mn L₃ edge to probe dd excitations. The local nature of dd RIXS spectroscopy permits one to use a single-site model to simulate the experimental spectra. The simulated spectra reproduce the in-plane [100] experimental RIXS spectrum. We also predict the intensity for the in-plane [110] direction and the out-of-plane spin orientation configuration [001]. Based on the single-ion model we were able to fit the experimental data to obtain the crystal field parameters (∆Eeg, ∆Et2g), the 10Dq value, and the intra-orbital spin-flip energy 2𝓙 (or 3JH, where JH is the Hund’s energy) of the Mn3+ ion. Utilizing our computed RIXS quantum transition amplitudes between the various d orbitals of the Mn3+ ion, the expression for the Kramers-Heisenberg cross section, and a self-consistent fitting procedure we also identify the energy boundaries of the non-spin-flip and spin-flip dd excitations present in the experimental data. From our fitting procedure we obtain 2𝓙(3JH)= 2.06 eV, a value which is in excellent agreement with that computed from the free ion Racah parameters. We also identified the charge transfer boundary. In addition to predicting the microscopic parameters, we find a quantum spin-flip transition in the non-cross (σin − σout, πin − πout) x-ray polarization channels of the dd RIXS spectra. A similar transition, was previously predicted to occur in the π – π channel of the magnon spectrum in the non-collinear non-coplanar Kagome compound composed of Cu2+ 3d⁹ ion.

Keywords: resonant inelastic x-ray scattering, spin-flip transition, antiferromagnetic order