@article{7246deecc1be4a30805e2393bc96fa86,
title = "Spin-orbital liquid in Ba3CuSb2 O9 stabilized by oxygen holes",
abstract = "We report x-ray and optical absorption spectroscopy as well as hard x-ray photoemission spectroscopy on hexagonal Ba3CuSb2O9 in which a Cu 3d spin-orbital liquid state is suggested from absence of the Jahn-Teller distortion of Cu2+O6 octahedra and of the magnetic ordering. The experimental results and their cluster model analysis indicate that O 2p holes play a crucial role in realizing the spin-orbital liquid state of hexagonal Ba3CuSb2O9. These oxygen holes appear due to the {"}reaction{"}Sb5+→Sb3++ two O 2p holes, with these holes being able to attach to Cu ions. The present work opens avenues towards spin-charge-orbital entangled liquid state in transition-metal oxides with small or negative charge transfer energy.",
author = "Kou Takubo and Huiyuan Man and Satoru Nakatsuji and Kohei Yamamoto and Yujun Zhang and Yasuyuki Hirata and Hiroki Wadati and Akira Yasui and Takashi Mizokawa and Khomskii, {Daniel I.}",
note = "Funding Information: We are grateful for fruitful discussions with and support from S. Koshihara and T. Ishikawa. XAS measurements were performed under the approval of Synchrotron Radiation Research Organization, the University of Tokyo (No. 2015A7401, 2018B7577). HAXPES measurements were performed under the approval of SPring-8 (No. 2018B1449). The work of D.I.K. is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project number 277146847, CRC 1238. Publisher Copyright: {\textcopyright} 2021 American Physical Society.",
year = "2021",
month = jul,
doi = "10.1103/PhysRevMaterials.5.075002",
language = "English",
volume = "5",
journal = "Physical Review Materials",
issn = "2475-9953",
publisher = "American Physical Society",
number = "7",
}