Combined experimental and theoretical study of hydrostatic (He-gas) pressure effects in \(\alpha\)-RuCl\(_3\)

• Published in: arXiv.org 2022-06
• Main Authors: Wolf, B, Kaib, D A S, Razpopov, A, Biswas, S, Riedl, K, Winter, S M, Valentí, R, Saito, Y, Hartmann, S, Vinokurova, E, Doert, T, Isaeva, A, Bastien, G, Wolter, A U B, Büchner, B, Lang, M
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Bonding strength; Density functional theory; Dimerization; Hydrostatic pressure; Magnetic permeability; Magnetic transitions; Phase transitions; Pressure dependence; Pressure effects; Stacking faults
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2206.13178

We report a detailed experimental and theoretical study on the effect of hydrostatic pressure on the structural and magnetic aspects of the layered honeycomb antiferromagent \(\alpha\)-RuCl\(_{3}\). Magnetic susceptibility measurements performed under almost ideal hydrostatic-pressure conditions yield that the phase transition to zigzag-type antiferromagnetic order at \(T_N\) = 7.3 K can be rapidly suppressed to about 6.1 K. A further suppression with increasing pressure is impeded due to the occurrence of a pressure-induced structural transition at \(p \geq\) 104 MPa, accompanied by a strong dimerization of Ru-Ru bonds, which gives rise to a collapse of the magnetic susceptibility. Whereas the dimerization transition is strongly first order, as reflected by large discontinuous changes in \(\chi\) and pronounced hysteresis effects, the magnetic transition under varying pressure and magnetic field also reveals indications for a weakly first-order transition. We assign this observation to a strong magnetoelastic coupling in this system. Measurements of \(\chi\) under varying pressure in the paramagnetic regime (\(T > T_N\)) and before dimerization (\(p