Two-step growth of high-quality single crystals of the Kitaev magnet $\alpha$-RuCl$_{3}$
| Autor: | Namba, R., Imamura, K., Ishioka, R., Ishihara, K., Miyamoto, T., Okamoto, H., Shimizu, Y., Saito, Y., Agarmani, Y., Lang, M., Murayama, H., Xing, Y., Suetsugu, S., Kasahara, Y., Matsuda, Y., Hashimoto, K., Shibauchi, T. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | Phys. Rev. Materials 8, 074404 (2024) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevMaterials.8.074404 |
| Popis: | The layered honeycomb magnet $\alpha$-RuCl$_3$ is the most promising candidate for a Kitaev quantum spin liquid (KQSL) that can host charge-neutral Majorana fermions. Recent studies have shown significant sample dependence of thermal transport properties, which are a key probe of Majorana quasiparticles in the KQSL state, highlighting the importance of preparing high-quality single crystals of $\alpha$-RuCl$_3$. Here, we present a relatively simple and reliable method to grow high-quality single crystals of $\alpha$-RuCl$_3$. We use a two-step crystal growth method consisting of a purification process by chemical vapor transport (CVT) and a main crystal growth process by sublimation. The obtained crystals exhibit a distinct first-order structural phase transition from the monoclinic ($C2/m$) to the rhombohedral ($R\bar{3}$) structure at $\sim150$ K, which is confirmed by the nuclear quadrupole resonance spectra with much sharper widths than previously reported. The Raman spectra show the absence of defect-induced modes, supporting the good crystallinity of our samples. The jumps in the thermal expansion coefficient and specific heat at the antiferromagnetic (AFM) transition at 7.6-7.7 K are larger and sharper than those of previous samples grown by the CVT and Bridgman methods and do not show any additional AFM transitions at 10-14 K due to stacking faults. The longitudinal thermal conductivity in the AFM phase is significantly larger than previously reported, indicating a very long mean free path of heat carriers. All the results indicate that our single crystals are of superior quality with good crystallinity and few stacking faults, which provides a suitable platform for studying the Kitaev physics. Comment: 9 pages, 7 figures |
| Databáze: | arXiv |
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