Spin-orbit tuned metal-insulator transitions in single-crystal Sr2Ir1−xRhxO4(0≤x≤1)
Spin-orbit tuned metal-insulator transitions in single-crystal Sr2Ir1−xRhxO4(0≤x≤1)
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DOI：
10.1103/physrevb.86.125105
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发表时间：
2012-07
影响因子：
3.7
通讯作者：
T. Qi;O. Korneta;L. Li;K. Butrouna;V. S. Cao;X. Wan;P. Schlottmann;R. Kaul;G. Cao
中科院分区：
文献类型：
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作者：
T. Qi;O. Korneta;L. Li;K. Butrouna;V. S. Cao;X. Wan;P. Schlottmann;R. Kaul;G. Cao
SR₂IrO₄是由自旋-轨道相互作用驱动的磁性绝缘体，而等电子、等结构的SR₂Rho₄是顺磁性金属。对比的基态已经被证明是由于强SOI在Irate中的关键作用。我们的结构、输运、磁性和热学性质的研究表明，用4d Rh⁴⁺(4d⁵)离子取代5d Ir⁴⁺(5d⁵)离子直接降低了₂IrO₄中的SOI，重新平衡了竞争能量，从而产生了丰富的₂Ir1-xRhxO₄相图，具有两个主要效应：(1)轻Rh掺杂(0≤x≤0.16)引起电阻率和磁有序温度TC同时急剧下降，在x=0.16时被抑制到零，x=0时为240K。(2)当Rh掺杂量较大时，[0.2 4；x&t；0.85(±0.0 5)]的无序散射导致局域态和返回绝缘态，自旋受挫和奇异的磁性行为只在x=1附近消失。通过与锶₂ir1-xRuxO₄的比较，进一步突出了SR₂ir1-xRuxO₄的复杂性，其中Ru⁴⁺(4d⁴)驱动从绝缘态到金属态的直接交叉。
Sr₂IrO₄ is a magnetic insulator driven by spin-orbit interaction (SOI) whereas the isoelectronic and isostructural Sr₂RhO₄ is a paramagnetic metal. The contrasting ground states have been shown to result from the critical role of the strong SOI in the iridate. Our investigation of structural, transport, magnetic, and thermal properties reveals that substituting 4d Rh⁴⁺ (4d⁵) ions for 5d Ir⁴⁺ (5d⁵) ions in Sr₂IrO₄ directly reduces the SOI and rebalances the competing energies so profoundly that it generates a rich phase diagram for Sr₂Ir1–xRhxO₄ featuring two major effects: (1) Light Rh doping (0 ≤ x ≤ 0.16) prompts a simultaneous and precipitous drop in both the electrical resistivity and the magnetic ordering temperature TC, which is suppressed to zero at x = 0.16 from 240 K at x = 0. (2) However, with heavier Rh doping [0.24 < x < 0.85 (±0.05)] disorder scattering leads to localized states and a return to an insulating state with spin frustration and exotic magnetic behavior that only disappears near x = 1. The intricacy of Sr₂Ir1–xRhxO₄ is further highlighted by comparison with Sr₂Ir1–xRuxO₄ where Ru⁴⁺ (4d⁴) drives a direct crossover from the insulating to metallic states.