自旋-轨道耦合型莫特绝缘体Sr2IrO4的高压拉曼光谱

尹霞 张建波 丁阳

尹霞, 张建波, 丁阳. 自旋-轨道耦合型莫特绝缘体Sr2IrO4的高压拉曼光谱[J]. 高压物理学报, 2020, 34(4): 040103. doi: 10.11858/gywlxb.20190865
引用本文: 尹霞, 张建波, 丁阳. 自旋-轨道耦合型莫特绝缘体Sr2IrO4的高压拉曼光谱[J]. 高压物理学报, 2020, 34(4): 040103. doi: 10.11858/gywlxb.20190865
YIN Xia, ZHANG Jianbo, DING Yang. Raman Scattering of Spin-Orbit Mott Insulator Sr2IrO4 at High-Pressure[J]. Chinese Journal of High Pressure Physics, 2020, 34(4): 040103. doi: 10.11858/gywlxb.20190865
Citation: YIN Xia, ZHANG Jianbo, DING Yang. Raman Scattering of Spin-Orbit Mott Insulator Sr2IrO4 at High-Pressure[J]. Chinese Journal of High Pressure Physics, 2020, 34(4): 040103. doi: 10.11858/gywlxb.20190865

自旋-轨道耦合型莫特绝缘体Sr2IrO4的高压拉曼光谱

doi: 10.11858/gywlxb.20190865
基金项目: 国家重点研发计划(2018YFA0305703);国家自然科学基金委-中国工程物理研究院NSAF联合基金(U1930401);国家自然科学基金(11874075);科学挑战专题(TZ2016001)
详细信息
    作者简介:

    尹 霞(1993-),女,硕士研究生,主要从事高压凝聚态物理研究. E-mail:xia.yin@hpstar.ac.cn

    通讯作者:

    丁 阳(1968-),男,博士,研究员,主要从事高压凝聚态物理研究.E-mail:yang.ding@hpstar.ac.cn

  • 中图分类号: O469;O521.2

Raman Scattering of Spin-Orbit Mott Insulator Sr2IrO4 at High-Pressure

  • 摘要: 5d过渡金属化合物内部的电子相互作用(U)、自旋-轨道耦合(SOC)、晶体场效应呈现既耦合又竞争的复杂关系。这些耦合竞争关系可以在温度、磁场或压力调控下诱发许多新奇的电磁性质,成为当前凝聚态物理的研究热点之一。通过对目前研究最多的化合物Sr2IrO4单晶进行常温高压下的拉曼光谱分析发现,加压至19.6~22.2 GPa时,拉曼光谱在波数为199 cm–1处出现新峰,清楚表明结构发生了相变,而该相变在此前一直无法确认。进一步的研究表明:这种结构相变的发生独立于低温下的磁性相变,可以通过自旋-轨道耦合对高压下Sr2IrO4的磁有序消失起到决定性作用。实验结果揭示了利用莫特绝缘体晶格变化来调控其电磁特性的新途径,也为未来设计新型功能材料提供了新思路。

     

  • 图  常温常压下不同波长、功率、极化角度的Sr2IrO4拉曼峰

    Figure  1.  Raman peaks of Sr2IrO4 measured at different wavelengths, powers and polarization angles at ambient condition

    图  常温常压下测得的单晶Sr2IrO4的拉曼峰

    Figure  2.  Raman peaks of single crystal Sr2IrO4 at ambient condition

    图  Sr2IrO4在80~580 cm–1处的拉曼峰及其频移、最强峰半高宽(FWHM)随压力的变化

    Figure  3.  Variation of Raman peak of Sr2IrO4 at 80–580 cm–1 with Raman shift and FWHM under high pressure

    图  Sr2IrO4在580~980 cm–1处的拉曼峰及其频移、最强峰半高宽随压力的变化

    Figure  4.  Variation of Raman peak of Sr2IrO4 at 580–980 cm–1 with Raman shift versus and FWHM under high pressure

    图  Sr2IrO4在1 476 cm–1处的拉曼峰及其频移随压力的变化

    Figure  5.  Variation of Raman peak of Sr2IrO4 at 1 476 cm–1 with Raman shift versus under high pressure

    表  1  常温常压下单晶Sr2IrO4的拉曼峰振动模式指认与文献对比

    Table  1.   Frequencies and assignments about Raman modes of single crystal Sr2IrO4 at ambient condition

    Mode Frequency/cm–1
    AssignmentThis workRef.[20-21]
    A1g (Sr against IrO6)ν1 181 187
    A1g (Ir—O—Ir bending)ν2 263 277
    A1g (Oxygen)ν3 387 392
    A1g (Oxygen)ν4 556 560
    B1g (Oxygen)ν5 675 666
    B1g (Oxygen)ν6 699 690
    B1g (Oxygen, breathing)ν7 723 728
    Two-phonon of 728 cm–1ν81 4761 467
    下载: 导出CSV
  • [1] WITCZAK-KREMPA W, CHEN G, KIM Y B, et al. Correlated quantum phenomena in the strong spin-orbit regime [J]. Annual Review of Condensed Matter Physics, 2014, 5(1): 57–82. doi: 10.1146/annurev-conmatphys-020911-125138
    [2] WANG F, SENTHIL T. Twisted hubbard model for Sr2IrO4: magnetism and possible high temperature superconductivity [J]. Physical Review Letters, 2011, 106(13): 136402.
    [3] KITAGAWA K, TAKAYAMA T, MATSUMOTO Y, et al. A spin-orbital-entangled quantum liquid on a honeycomb lattice [J]. Nature, 2018, 554(7692): 341–345. doi: 10.1038/nature25482
    [4] PRICE C C, PERKINS N B. Critical properties of the Kitaev-Heisenberg model [J]. Physical Review Letters, 2012, 109(18): 187201. doi: 10.1103/PhysRevLett.109.187201
    [5] CHALOUPKA J, JACKELI G, KHALIULLIN G. Zigzag magnetic order in the iridium oxide Na2IrO3 [J]. Physical Review Letters, 2013, 110(9): 097204. doi: 10.1103/PhysRevLett.110.097204
    [6] WATANABE H, SHIRAKAWA T, YUNOKI S. Monte carlo study of an unconventional superconducting phase in iridium oxide Jeff = 1/2 mott insulators induced by carrier doping [J]. Physical Review Letters, 2013, 110: 027002. doi: 10.1103/PhysRevLett.110.027002
    [7] YONEZAWA S, MURAOKA Y, MATSUSHITA Y, et al. Superconductivity in a pyrochlore-related oxide KOs2O6 [J]. Journal of Physics:Condensed Matter, 2004, 16(3): L9–L12. doi: 10.1088/0953-8984/16/3/L01
    [8] KIM B J, JIN H, MOON S J, et al. Novel Jeff = 1/2 mott state induced by relativistic spin-orbit coupling in Sr2IrO4 [J]. Physical Review Letters, 2008, 101(7): 076402. doi: 10.1103/PhysRevLett.101.076402
    [9] RAU J G, LEE K H, KEE H Y. Spin-orbit physics giving rise to novel phases in correlated systems: iridates and related materials [J]. Condensed Matter Physics, 2015, 7(7).
    [10] ARITA R, KUNEŠ J, KOZHEVNIKOV A V, et al. Ab initio studies on the interplay between spin-orbit interaction and coulomb correlation in Sr2IrO4 and Ba2IrO4 [J]. Physical Review Letters, 2012, 108(8): 086403. doi: 10.1103/PhysRevLett.108.086403
    [11] LI Q, CAO G, OKAMOTO S, et al. Atomically resolved spectroscopic study of Sr2IrO4: experiment and theory [J]. Scientific Reports, 2013: 3.
    [12] CAO G, SCHLOTTMANN P. The challenge of spin-orbit-tuned ground states in iridates: a key issues review [J]. Reports on Progress in Physics Physical Society, 2018, 81(4): 042502. doi: 10.1088/1361-6633/aaa979
    [13] GRETARSSON H, SUNG N H, HOEPPNER M, et al. Two-magnon Raman scattering and Pseudospin-Lattice interactions in Sr2IrO4 and Sr3Ir2O7 [J]. Physical Review Letters, 2016, 116(13): 136401. doi: 10.1103/PhysRevLett.116.136401
    [14] CAO G, TERZIC J, ZHAO H D, et al. Electrical control of structural and physical properties via strong spin-orbit interactions in Sr2IrO4 [J]. Physical Review Letters, 2017, 120(1): 017201.
    [15] LIU H, KHALIULLIN G. Pseudo Jahn-Teller effect and magnetoelastic coupling in spin-orbit mott insulators [J]. Physical Review Letters, 2019, 122(5): 057203. doi: 10.1103/PhysRevLett.122.057203
    [16] HASKEL D, FABBRIS G, ZHERNENKOV M, et al. Pressure tuning of the spin-orbit coupled ground state in Sr2IrO4 [J]. Physical Review Letters, 2012, 109(2): 027204. doi: 10.1103/PhysRevLett.109.027204
    [17] SAMANTA K, ARDITO F M, SOUZA-NETO N M, et al. First-order structural transition and pressure-induced lattice/phonon anomalies in Sr2IrO4 [J]. Physical Review B, 2018, 98: 094101. doi: 10.1103/PhysRevB.98.094101
    [18] CHEN C, ZHOU Y, CHEN X, et al. Persistent insulator: avoidance of metallization at megabar pressures in strongly spin-orbit-coupled Sr2IrO4 [EB/OL]. arXiv: 1910. 10291 [2019-12-05].
    [19] CHIJIOKE A D, NELLIS W J, SOLDATOV A, et al. The ruby pressure standard to 150 GPa [J]. Journal of Applied Physics, 2005, 98(11): 094112.
    [20] AROYO, MOIS ILIA, PEREZ-MATO, et al. Bilbao crystallographic server: I. databases and crystallographic computing programs [J]. Zeitschrift Für Kristallographie, 2006, 221(1): 15.
    [21] CETIN M F, LEMMENS P, GNEZDILOV V, et al. Crossover from coherent to incoherent scattering in spin-orbit dominated Sr2IrO4 [J]. Physical Review B, 2012, 85(19): 195148. doi: 10.1103/PhysRevB.85.195148
    [22] MOON S J, JIN H, CHOI W S, et al. Temperature dependence of the electronic structure of the Jeff = 1/2 mott insulator Sr2IrO4 studied by optical spectroscopy [J]. Physical Review B, 2009, 80(19): 195110. doi: 10.1103/PhysRevB.80.195110
    [23] ZHANG J B, YAN D Y, SORB Y A, et al. Lattice frustration in spin-orbit mott insulator Sr3Ir2O7 at high pressure [J]. NPJ Quantum Mater, 2019, 4(23).
    [24] CRAWFORD M K, SUBRAMANIAN M A, HARLOW R L, et al. Structural and magnetic studies of Sr2IrO4 [J]. Physical Review B, 1994, 49(13): 9198–9201. doi: 10.1103/PhysRevB.49.9198
    [25] YE F, CHI S, CHAKOUMAKOS B C, et al. The magnetic and crystal structures of Sr2IrO4: a neutron diffraction study [J]. Physical Review B, 2013, 87(14): 545–579.
    [26] KIM B J, OHSUMI H, KOMESU T, et al. Phase-sensitive observation of a spin-orbital mott state in Sr2IrO4 [J]. Science, 2009, 323(5919): 1329–1332. doi: 10.1126/science.1167106
  • 加载中
图(5) / 表(1)
计量
  • 文章访问数:  7196
  • HTML全文浏览量:  2933
  • PDF下载量:  37
出版历程
  • 收稿日期:  2019-12-05
  • 修回日期:  2019-12-10
  • 发布日期:  2020-02-25

目录

    /

    返回文章
    返回