Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 64: Frustrated Magnets - α-RuCl₃ and Cu-based Materials

TT 64.3: Vortrag

Mittwoch, 14. März 2018, 15:30–15:45, HFT-FT 101

Pressure induced structural phase transition and dimer formation in α-RuCl₃ — •Maximilian Kusch¹, Quirin Stahl¹, Theo Woike¹, Gaston Garbarino², Francisco Javier Martinez², Mohamed Mezouar², Lisa Leissner³, Kwang-Yong Choi⁴, and Jochen Geck¹ — ¹Institute of Solid State and Materials Physics, TU Dresden, 01069 Dresden, Germany — ²European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France — ³Institut für Anorganische Chemie, Technische Universität Bergakademie Freiberg, D-09596 Freiberg, Germany — ⁴Department of Physics, Chung-Ang University, Seoul 156-756, Republic of Korea

Currently α-RuCl₃ is the most promising candidate for the long sought realization of the Kitaev model, which is believed to be very close to a gapless spin-liquid. Under ambient conditions, however, α-RuCl₃ exhibits antiferromagnetic ordering below 7K, but several experimental studies indicate the proximity to the Kitaev limit nonetheless. In accordance very recent magnetization measurements as a function of pressure revealed a significant decrease in the magnetization. We therefore performed single crystal XRD as a function of pressure in the range < 2GPa at 4 - 300K to determine the structural changes related to the magnetic transition. Our study shows that the monoclinic phase under ambient conditions transforms into a metastabile hexagonal phase followed by a trigonal phase featuring strong Ru-Ru dimer bonds. Specifically the latter transition coincides with the observation of a significant decrease in the magnetization. One possible explanation for this effect is the formation of a S=0 singlet state on the Ru-Ru dimers.