中国物理B ›› 2021, Vol. 30 ›› Issue (6): 67402-067402.doi: 10.1088/1674-1056/abf100

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Pressure-induced anomalous insulating behavior in frustrated iridate La3Ir3O11

Chun-Hua Chen(陈春华)1,2, Yong-Hui Zhou(周永惠)1,†, Ying Zhou(周颖)3, Yi-Fang Yuan(袁亦方)1,2, Chao An(安超)3, Xu-Liang Chen(陈绪亮)1, Zhao-Ming Tian(田召明)4, and Zhao-Rong Yang(杨昭荣)1,3,5,‡   

  1. 1 Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China;
    2 Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China;
    3 Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China;
    4 School of Physics, and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China;
    5 High Magnetic Field Laboratory of Anhui Province, Hefei 230031, China
  • 收稿日期:2021-02-21 修回日期:2021-03-05 接受日期:2021-03-23 出版日期:2021-05-18 发布日期:2021-05-27
  • 通讯作者: Yong-Hui Zhou, Zhao-Rong Yang E-mail:yhzhou@hmfl.ac.cn;zryang@issp.ac.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant Nos. 2018YFA0305704 and 2016YFA0401804), the National Natural Science Foundation of China (Grant Nos. U1632275, U1932152, 11874362, 11704387, 11804344, 11804341, 11974016, U19A2093, and U1832209), the Natural Science Foundation of Anhui Province, China (Grant Nos. 1808085MA06, 2008085QA40, and 1908085QA18), the Users with Excellence Project of Hefei Center CAS (Grant No. 2020HSC-UE015), and the Collaborative Innovation Program of Hefei Science Center CAS (Grant No. 2020HSC-CIP014). A portion of this work was supported by the High Magnetic Field Laboratory of Anhui Province under Contract No. AHHM-FX-2020-02. Yonghui Zhou was supported by the Youth Innovation Promotion Association CAS (Grant No. 2020443).

Pressure-induced anomalous insulating behavior in frustrated iridate La3Ir3O11

Chun-Hua Chen(陈春华)1,2, Yong-Hui Zhou(周永惠)1,†, Ying Zhou(周颖)3, Yi-Fang Yuan(袁亦方)1,2, Chao An(安超)3, Xu-Liang Chen(陈绪亮)1, Zhao-Ming Tian(田召明)4, and Zhao-Rong Yang(杨昭荣)1,3,5,‡   

  1. 1 Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China;
    2 Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China;
    3 Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China;
    4 School of Physics, and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China;
    5 High Magnetic Field Laboratory of Anhui Province, Hefei 230031, China
  • Received:2021-02-21 Revised:2021-03-05 Accepted:2021-03-23 Online:2021-05-18 Published:2021-05-27
  • Contact: Yong-Hui Zhou, Zhao-Rong Yang E-mail:yhzhou@hmfl.ac.cn;zryang@issp.ac.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant Nos. 2018YFA0305704 and 2016YFA0401804), the National Natural Science Foundation of China (Grant Nos. U1632275, U1932152, 11874362, 11704387, 11804344, 11804341, 11974016, U19A2093, and U1832209), the Natural Science Foundation of Anhui Province, China (Grant Nos. 1808085MA06, 2008085QA40, and 1908085QA18), the Users with Excellence Project of Hefei Center CAS (Grant No. 2020HSC-UE015), and the Collaborative Innovation Program of Hefei Science Center CAS (Grant No. 2020HSC-CIP014). A portion of this work was supported by the High Magnetic Field Laboratory of Anhui Province under Contract No. AHHM-FX-2020-02. Yonghui Zhou was supported by the Youth Innovation Promotion Association CAS (Grant No. 2020443).

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摘要： The geometrically frustrated iridate La3Ir3O11 with strong spin-orbit coupling and fractional valence was recently predicted to be a quantum spin liquid candidate at ambient conditions. Here, we systematically investigate the evolution of structural and electronic properties of La3Ir3O11 under high pressure. Electrical transport measurements reveal an abnormal insulating behavior rather than metallization above a critical pressure Pc ~38.7 GPa. Synchrotron x-ray diffraction (XRD) experiments indicate the stability of the pristine cubic KSbO3-type structure up to 73.1 GPa. Nevertheless, when the pressure gradually increases across Pc, the bulk modulus gets enhanced and the pressure dependence of bond length dIr-Ir undergoes a slope change. Consistent with the XRD data, detailed analyses of Raman spectra reveal an abnormal redshift of Raman mode and a change of Raman intensity around Pc. Our results demonstrate that the pressure-induced insulating behavior in La3Ir3O11 can be assigned to the structural modification, such as the distortion of IrO6 octahedra. These findings will shed light on the emergent abnormal insulating behavior in other 5d iridates reported recently.

关键词: high pressure, 5d iridates, semimetal-insulator transition, crystal structure

Abstract: The geometrically frustrated iridate La3Ir3O11 with strong spin-orbit coupling and fractional valence was recently predicted to be a quantum spin liquid candidate at ambient conditions. Here, we systematically investigate the evolution of structural and electronic properties of La3Ir3O11 under high pressure. Electrical transport measurements reveal an abnormal insulating behavior rather than metallization above a critical pressure Pc ~38.7 GPa. Synchrotron x-ray diffraction (XRD) experiments indicate the stability of the pristine cubic KSbO3-type structure up to 73.1 GPa. Nevertheless, when the pressure gradually increases across Pc, the bulk modulus gets enhanced and the pressure dependence of bond length dIr-Ir undergoes a slope change. Consistent with the XRD data, detailed analyses of Raman spectra reveal an abnormal redshift of Raman mode and a change of Raman intensity around Pc. Our results demonstrate that the pressure-induced insulating behavior in La3Ir3O11 can be assigned to the structural modification, such as the distortion of IrO6 octahedra. These findings will shed light on the emergent abnormal insulating behavior in other 5d iridates reported recently.

Key words: high pressure, 5d iridates, semimetal-insulator transition, crystal structure

中图分类号:  (Effects of pressure)

  • 74.62.Fj
72.80.Ga (Transition-metal compounds) 71.30.+h (Metal-insulator transitions and other electronic transitions) 74.62.Bf (Effects of material synthesis, crystal structure, and chemical composition)