Field-induced quantum criticality in the Kitaev system $\alpha$-RuCl$_3$
| Autor: | Wolter, A. U. B., Corredor, L. T., Janssen, L., Nenkov, K., Schönecker, S., Do, S. -H., Choi, K. -Y., Albrecht, R., Hunger, J., Doert, T., Vojta, M., Büchner, B. |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 96, 041405 (2017) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.96.041405 |
| Popis: | $\alpha$-RuCl$_3$ has attracted enormous attention since it has been proposed as a prime candidate to study fractionalized magnetic excitations akin to Kitaev's honeycomb-lattice spin liquid. We have performed a detailed specific-heat investigation at temperatures down to $0.4$ K in applied magnetic fields up to $9$ T for fields parallel to the $ab$ plane. We find a suppression of the zero-field antiferromagnetic order, together with an increase of the low-temperature specific heat, with increasing field up to $\mu_0H_c\approx 6.9$ T. Above $H_c$, the magnetic contribution to the low-temperature specific heat is strongly suppressed, implying the opening of a spin-excitation gap. Our data point toward a field-induced quantum critical point (QCP) at $H_c$; this is supported by universal scaling behavior near $H_c$. Remarkably, the data also reveal the existence of a small characteristic energy scale well below $1$~meV above which the excitation spectrum changes qualitatively. We relate the data to theoretical calculations based on a $J_1$--$K_1$--$\Gamma_1$--$J_3$ honeycomb model. Comment: 5 pages, 4 figures (main text), plus Supplemental Material |
| Databáze: | arXiv |
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