Charge partitioning and anomalous hole doping in Rh-doped 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Sr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>IrO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>

Saito, Chikara; Fabbris, G.; Terzic, Jasminka; Cao, Gang; Khomskii, Daniel I.; Haskel, D.

doi:10.1103/physrevb.95.060407

Cited by 28 publications

(32 citation statements)

References 39 publications

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“…This means more possibilities for emergent electronic phases [23]. Known methods for hole doping of Sr 2 IrO 4 include K doping [117] (not to be confused with K deposition discussed above) and Rh substitution in place of Ir [106,107,110,118,126,127]. Although Rh and Ir are in the same column of the periodic [129], and localization of carriers at low temperatures [106].…”

Section: Hole Dopingmentioning

confidence: 99%

Square Lattice Iridates

Bertinshaw

Kim

Khaliullin

et al. 2019

Annu. Rev. Condens. Matter Phys.

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Over the last few years, Sr 2 IrO 4 , a single-layer member of the Ruddlesden-Popper series iridates, has received much attention as a close analog of cuprate high-temperature superconductors.Although there is not yet firm evidence for superconductivity, a remarkable range of cuprate phenomenology has been reproduced in electron-and hole-doped iridates including pseudogaps, Fermi arcs, and d-wave gaps. Further, a number of symmetry breaking orders reminiscent of those decorating the cuprate phase diagram have been reported using various experimental probes. We discuss how the electronic structures of Sr 2 IrO 4 through strong spin-orbit coupling leads to the low-energy physics that had long been unique to cuprates, what the similarities and differences between cuprates and iridates are, and how these advance the field of high-temperature superconductivity by isolating essential ingredients of superconductivity from a rich array of phenomena that surround it. Finally, we comment on the prospect of finding a new high-temperature superconductor based on the iridate series. b c a Sr O Ir a b c pseudospin-1/2 J a b FIG. 1. Crystal and magnetic structures of Sr 2 IrO 4 . (a) The crystal structure is based on Ref. [26] according to which the space group is I4 1 /acd. However, recent studies indicate that the symmetry is lower and most probably is I4 1 /a [27-29]. (b) Quasi-2D network of Ir and O. (c) The magnetic structure from Ref. [2]. II. MAPPING ONTO CUPRATE PHYSICSSoon after the discovery of HTSC in the cuprates, many complex oxides with a K 2 NiF 4 structure (isostructural to La 2 CuO 4 ) and its variants were searched for signs of superconductivity. Among these were Sr 2 RhO 4 and Sr 2 IrO 4 [30], which are "one-hole" systems, albeit with a t 2g -hole in the low-spin d 5 configuration as opposed to an e g -hole in cuprates. However, it was quickly apparent that 4d and 5d systems tend to be rather weakly correlated. In fact, Sr 2 RhO 4 is a Fermi liquid metal [31, 32] with a Fermi surface understood qualitatively in terms of a band structure calculated using density functional theory within the local density approximation (LDA) [33, 34]. Interestingly, the Fermi surfaces of Sr 2 RhO 4 and Sr 2 IrO 4 , calculated without SOC, are near indistinguishable due to their almost identical crystal structures with less than 1% difference in their lattice parameters [30]. A closer inspection, however, reveals that LDA does not accurately replicate the measured FermiX M X E-μ (eV) E-μ (eV) E-μ (eV) M X Γ Γ Γ Γ Γ Γ U ζ ζ μ wide band metal narrow J eff =1/2 band J eff =1/2 Mott state LDA+SOC LDA LDA+SOC+U t 2g band J eff =1/2 band J eff =3/2 band J eff =3/2 band J eff =1/2 UHB J eff =1/2 LHB FIG. 2. Illustration of the SOC driven Mott transition. Introduction of SOC splits off a narrow band near the Fermi level (orange solid lines), for which a moderate Coulomb interaction U ∼2 eV is sufficient to open a gap.observation of a significant gap reduction across T N , a typical Slater behavior, supports this viewpoint [42,43]. On th...

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Section: Hole Dopingmentioning

confidence: 99%

Square Lattice Iridates

Bertinshaw

Kim

Khaliullin

et al. 2019

Annu. Rev. Condens. Matter Phys.

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“…Recent ARPES measurements [18] suggest that hybridization with Rh dopants dilutes the SOC present in the system, driving the system into a metallic state. On the other side, Ir and Rh L 2,3edge x-ray absorption indicates that Rh impurities assume a 3+ valence [19,20], suggesting that holes are introduced in a charge compensation process. In this picture, only a relatively small fraction of Ir ions ever assumes a 5+ oxidation state, potentially as a result of disorder on the Ir site [15,20].…”

Section: Introductionmentioning

confidence: 99%

Spin-wave gap collapse in Rh-doped Sr2IrO4

et al. 2020

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We use resonant inelastic x-ray scattering (RIXS) at the Ir L 3 edge to study the effect of hole doping upon the J eff = 1 2 Mott-insulating state in Sr 2 IrO 4 , via Rh replacement of the Ir site. The spin-wave gap, associated with XY-type spin-exchange anisotropy, collapses with increasing Rh content, prior to the suppression of the Mott-insulating state and in contrast to electron doping via La substitution of the Sr site. At the same time, despite heavy damping, the d-d excitation spectra retain their overall amplitude and dispersion character. A careful study of the spin-wave spectrum reveals that deviations from the J 1 -J 2 -J 3 Heisenberg used to model the pristine system disappear at intermediate doping levels. These findings are interpreted in terms of a modulation of Ir-Ir correlations due to the influence of Rh impurities upon nearby Ir wave functions, even as the single-band J eff = 1 2 model remains valid up to full carrier delocalization. They underline the importance of the transition metal site symmetry when doping pseudospin systems such as Sr 2 IrO 4 .

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“…It has been suggested that the spin-orbital entanglement induced by the strong SOC in these structures could make these materials hosts for several unconventional features such as the Kitaev model [2,3], quantum spin Hall effect at room temperature [4], or unconventional superconductivity [5,6]. In addition, doped carriers in the spin-orbital entangled Mott insulating state in the iridates are expected to show many novel features and are also the subject of several recent studies [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Electronic structure and optical properties of Sr₂IrO₄ under epitaxial strain

2019

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We study the modification of the electronic structure in the strong spin-orbit coupled Sr 2 IrO 4 by epitaxial strain using density-functional methods. Structural optimization shows that strain changes the internal structural parameters such as the Ir-O-Ir bond angle, which has an important effect on the band structure. An interesting prediction is the Γ−X crossover of the valence band maximum with strain, while the conduction minimum at M remains unchanged. This in turn suggests strong strain dependence of the transport properties for the hole-doped system, but not when the system is electron doped. Taking the measured value of the Γ−X separation for the unstrained case, we predict the Γ−X crossover of the valence band maximum to occur for the tensile epitaxial strain e xx ≈3%. A minimal tight-binding model within the J eff =1/2 subspace is developed to describe the main features of the band structure. The optical absorption spectra under epitaxial strain are computed using densityfunctional theory, which explains the observed anisotropy in the optical spectra with the polarization of the incident light. We show that the optical transitions between the Ir (d) states, which are dipole forbidden, can be explained in terms of the admixture of Ir (p) orbitals with the Ir (d) bands.

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Charge partitioning and anomalous hole doping in Rh-doped Sr2IrO4

Cited by 28 publications

References 39 publications

Square Lattice Iridates

Square Lattice Iridates

Spin-wave gap collapse in Rh-doped Sr2IrO4

Electronic structure and optical properties of Sr₂IrO₄ under epitaxial strain

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Charge partitioning and anomalous hole doping in Rh-doped Sr2IrO4

Cited by 28 publications

References 39 publications

Square Lattice Iridates

Square Lattice Iridates

Spin-wave gap collapse in Rh-doped Sr2IrO4

Electronic structure and optical properties of Sr2IrO4 under epitaxial strain

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Product

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Electronic structure and optical properties of Sr₂IrO₄ under epitaxial strain