Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 64: Frustrated Magnets - α-RuCl3 and Cu-based Materials
TT 64.1: Vortrag
Mittwoch, 14. März 2018, 15:00–15:15, HFT-FT 101
Electronically highly cubic conditions for Ru in α-RuCl3 — •Stefano Agrestini1, Chang-Yang Kuo1, Kyung-Tae Ko1, Zhiwei Hu1, Deepa Kasinathan1, Hari Babu Vasili2, Javier Herrero-Martin2, Manuel Valvidares2, Eric Pellegrin2, Anne Henschel1, Marcus Schmidt1, Ling-Yun Jang3, Arata Tanaka4, and Liu Hao Tjeng1 — 1Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 2ALBA Synchrotron Light Source, Barcelona, Spain — 3NSRRC, Hsinchu, Taiwan — 4Department of Quantum Matter, Hiroshima University, Higashi-Hiroshima, Japan
α-RuCl3 is the most promising candidate for the long-sought materialization of the Kitaev model. Prerequisite for these expectations is that the non-cubic crystal field splitting is small compared to the spin-orbit coupling (SOC) and, hence, does not perturb in a significant way the description of the electronic ground state in terms of the Jeff = 1/2 state. In this context, contradictory reports are available in literature.
In this talk I present a study of the local Ru 4d electronic structure of RuCl3 by means of polarization dependent x-ray absorption spectroscopy at the Ru-L2,3 edges. The observed linear dichroism is vanishingly small indicating that electronically the Ru 4d local symmetry is highly cubic. Consistent with our magnetic circular dichroism measurements, the ratio of the orbital and spin moments is found to be 2.0, the value expected for a Jeff = 1/2 ground state. The data thus show that as far as the Ru 4d local properties are concerned, RuCl3 is an ideal candidate for the realization of the Kitaev physics.