Oike Hiroshi, Suzuki Yuji, Taniguchi Hiromi, Seki Yasuhide, Miyagawa Kazuya, Kanoda Kazushi
Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.
RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan.
Nat Commun. 2017 Oct 2;8(1):756. doi: 10.1038/s41467-017-00941-6.
Quantum spin liquids are exotic Mott insulators that carry extraordinary spin excitations. Therefore, when doped, they are expected to afford metallic states with unconventional magnetic excitations. Here, we report experimental results which are suggestive of a doped spin liquid with anomalous metallicity in a triangular-lattice organic conductor. The spin susceptibility is nearly perfectly scaled to that of a non-doped spin liquid insulator in spite of the metallic state. Furthermore, the charge transport that is confined in the layer at high temperatures becomes sharply deconfined on cooling, coinciding with the rapid growth of spin correlations or coherence as signified by a steep decrease in spin susceptibility. The present results substantiate the desired doped spin liquid and suggest a strange metal, in which the coherence of the underlying spin liquid promotes the deconfinement of charge from the layers while preserving the non-Fermi-liquid nature.It is expected that introducing charge carriers into an exotic quantum spin liquid state may lead to an unconventional metal but there are no clear realizations of a metallic spin liquid. Here, the authors present a spin liquid candidate that also shows evidence of strange metal behavior.
量子自旋液体是具有非凡自旋激发的奇异莫特绝缘体。因此，当被掺杂时，预计它们会产生具有非常规磁激发的金属态。在此，我们报告了实验结果，这些结果表明在一种三角晶格有机导体中存在具有反常金属性的掺杂自旋液体。尽管处于金属态，但自旋磁化率几乎能完美地按比例缩放至非掺杂自旋液体绝缘体的磁化率。此外，在高温下局限于层内的电荷输运在冷却时会急剧解限，这与自旋关联或相干性的快速增长相吻合，自旋磁化率的急剧下降表明了这一点。目前的结果证实了所期望的掺杂自旋液体，并表明存在一种奇异金属，其中潜在自旋液体的相干性促进了电荷从层中的解限，同时保留了非费米液体性质。预计将电荷载流子引入奇异量子自旋液体状态可能会导致一种非常规金属，但目前尚无金属自旋液体的明确实例。在此，作者提出了一种自旋液体候选物，它也显示出奇异金属行为的证据。
