| Author |
Nozue, Yasuo Kimura, Kenta Hagiwara, Masayuki Wakabayashi, Yusuke Han, Yibo Ishiguro, Yuki Nasu, Joji Satake, Ryuta Nishibori, Eiji Yoshizawa, Masahito Ishihara, Sumio Nakano, Takehito Nakatsuji, Satoru Sawa, Hiroshi Nakanishi, Yoshiki Katayama, Naoyuki Drichko, Natalia Halim, Mario |
| Description |
Author Affiliation: Katayama N ( Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan); Kimura K ( Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan); Han Y ( Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Osaka 560-8531, Japan); Nasu J ( Department of Physics, Tohoku University, Sendai 980-8578, Japan); Drichko N ( Institute for Quantum Matter (IQM) and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218); Nakanishi Y ( Graduate School of Engineering, Iwate University, Morioka 020-8551, Japan); Halim M ( Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan); Ishiguro Y ( Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan); Satake R ( Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan); Nishibori E ( Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan); Yoshizawa M ( Graduate School of Engineering, Iwate University, Morioka 020-8551, Japan); Nakano T ( Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan); Nozue Y ( Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan); Wakabayashi Y ( Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan); Ishihara S ( Department of Physics, Tohoku University, Sendai 980-8578, Japan); Hagiwara M ( Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Osaka 560-8531, Japan); Sawa H ( Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan); Nakatsuji S ( Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan); |
| Abstract |
With decreasing temperature, liquids generally freeze into a solid state, losing entropy in the process. However, exceptions to this trend exist, such as quantum liquids, which may remain unfrozen down to absolute zero owing to strong quantum entanglement effects that stabilize a disordered state with zero entropy. Examples of such liquids include Bose-Einstein condensation of cold atoms, superconductivity, quantum Hall state of electron systems, and quantum spin liquid state in the frustrated magnets. Moreover, recent studies have clarified the possibility of another exotic quantum liquid state based on the spin-orbital entanglement in FeSc2S4. To confirm this exotic ground state, experiments based on single-crystalline samples are essential. However, no such single-crystal study has been reported to date. Here, we report, to our knowledge, the first single-crystal study on the spin-orbital liquid candidate, 6H-Ba3CuSb2O9, and we have confirmed the absence of an orbital frozen state. In strongly correlated electron systems, orbital ordering usually appears at high temperatures in a process accompanied by a lattice deformation, called a static Jahn-Teller distortion. By combining synchrotron X-ray diffraction, electron spin resonance, Raman spectroscopy, and ultrasound measurements, we find that the static Jahn-Teller distortion is absent in the present material, which indicates that orbital ordering is suppressed down to the lowest temperatures measured. We discuss how such an unusual feature is realized with the help of spin degree of freedom, leading to a spin-orbital entangled quantum liquid state. |
