Photoemission and x-ray absorption study of the electronic structure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>SrRu</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Ti</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>

Kim, Jungho; Kim, J.-Y.; Park, B.-G.; Oh, S.‐J.

doi:10.1103/physrevb.73.235109

Cited by 48 publications

(56 citation statements)

References 37 publications

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“…A prepeak at the same energy but notably higher intensity than A in Ba 3 Ti 2 RuO 9 has also been observed by others in the perovskite system SrRu 0.35 Ti 0.65 O 3 . 26 In that work the prepeak was assigned to Ru 4d states of mainly t 2g character.…”

Section: B O K Core Loss Edgementioning

confidence: 99%

Electronic structure and stability of hexagonalBa3Ti2RuO9

et al. 2010

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We investigated the electronic structure and stability of the hexagonal perovskite Ba 3 Ti 2 RuO 9 using highresolution electron energy loss spectroscopy and first-principles band structure calculations. The comparison between experimental and theoretical results leads to a coherent picture of the electronic structure of this compound where both Ti and Ru ions are tetravalent, the first unoccupied states being of Ru 4d character. Structural relaxations performed on four variants of this compound allowed a detailed investigation of the influence of the Ru atoms location in the hexagonal unit cell and clarified the origin of the stabilization of this phase at room temperature. Two structures without inversion symmetry built, respectively, with two TiRuO 9 units ͑space group P6 3 mc, 186͒ or with one Ru 2 O 9 and one Ti 2 O 9 unit ͑P6m2 , 187͒ are found to be the most stable. The stabilization of the first structure occurs through the polarization of the partially filled Ru 4d bands, whereas a direct metal-metal bonding interaction taking place between the two Ru atoms in the Ru 2 O 9 unit lowers the total energy of the second. The influence of the exchange correlation functional used to perform these calculations on the relative stability of the four variants is discussed.

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Section: B O K Core Loss Edgementioning

confidence: 99%

Electronic structure and stability of hexagonalBa3Ti2RuO9

et al. 2010

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“…Although this level of resolution has recently become possible, such high resolution has not been utilized so far for the present purpose. 15,16) We believe that our paper provides an incentive for such high-resolution photoemission experiments. In addition to such experiments, other experiments accessible to low energies are highly desirable for experimental confirmation of the present theory.…”

Section: à3mentioning

confidence: 99%

“…(5.5) and (5.6), with the transport properties of SrRu 1Àx Ti x O 3 , 14) where the breakdown of the ES scaling was indicated in photoemission experiments. 15,16) In Fig. 19, we show the experimental data for the DC resistivity of SrRu 1Àx Ti x O 3 at x ¼ 0:6, where the ground state is insulating.…”

Section: Comparison With Experimentsmentioning

confidence: 99%

Single-Particle Excitations under Coexisting Electron Correlation and Disorder: A Numerical Study of the Anderson–Hubbard Model

Shinaoka

Imada

2009

J. Phys. Soc. Jpn.

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Interplay of electron correlation and randomness is studied using the Anderson-Hubbard model within the Hartree-Fock (HF) approximation. Under the coexistence of short-range interaction and diagonal disorder, we obtain the ground-state phase diagram in three dimensions (3D), which includes an antiferromagnetic insulator, an antiferromagnetic metal, a paramagnetic insulator (Anderson-localized insulator), and a paramagnetic metal. Although only the short-range interaction is present in this model, we find unconventional soft gaps in the insulating phases irrespective of electron filling, spatial dimensions, and long-range order, where the single-particle density of states (DOS) vanishes with a power-law scaling in 1D or even faster in 2D and 3D toward the Fermi energy. We call such a gap a soft Hubbard gap. Moreover, exact-diagonalization results for 1D support the formation of a soft Hubbard gap beyond the mean-field level. The formation of the soft Hubbard gap cannot be attributed to the conventional theory by Efros and Shklovskii (ES) owing the emergence of soft gaps to the long-range Coulomb interaction. Indeed, on the basis of a multivalley energy landscape, we propose a phenomenological scaling theory, which predicts a scaling of the DOS, A in energy E as AðEÞ / exp½ÀðÀ log jE À E F jÞ d . Here, d is the spatial dimension, E F is the Fermi energy, and is a non universal constant. This scaling is in perfect agreement with the numerical results. We further discuss a correction of the scaling of the DOS by the long-range part of the Coulomb interaction, which modifies the ES scaling. Furthermore, explicit formulae for the temperature dependence of the DC resistivity via variable-range hopping under the influence of the soft gaps are derived. Finally, we compare the present theory with experimental results for SrRu 1Àx Ti x O 3 .

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“…In a similar B-site substituted transition-metal oxide SrRu 1−x Ti x O 3 , which demonstrates MIT at x ∼ 0.3 (SrRuO 3 is metallic), the depletion of the DOS near E F has shown an unusual |E − E F | 1.2 dependence in both metallic and insulating phases [7]. In addition, although it is believed that a disorder-induced insulator shows a soft Coulomb gap characterized by a (E − E F ) 2 dependence of the DOS near E F [8,9], the unexpected |E − E F | 3/2 dependence of the DOS near E F related to charge density wave has been observed in insulating BaIrO 3 [10].…”

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confidence: 99%

Critical Test for Altshuler-Aronov Theory: Evolution of the Density of States Singularity in Double PerovskiteSr2FeMoO6with Controlled Disorder

et al. 2007

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With high-resolution photoemission spectroscopy measurements, the density of states (DOS) near the Fermi level (EF) of double perovskite Sr2FeMoO6 having different degrees of Fe/Mo antisite disorder has been investigated with varying temperature. The DOS near EF showed a systematic depletion with increasing degree of disorder, and recovered with increasing temperature. AltshulerAronov (AA) theory of disordered metals well explains the dependences of the experimental results. Scaling analysis of the spectra provides experimental indication for the functional form of the AA DOS singularity.PACS numbers: 71.20.-b, 71.23.-k, 71.27.+a, 79.60.-i Disordered electronic systems, which have random potentials deviating from an ideal crystal, have been investigated from both fundamental and application points of view [1]. Ever since the finding of filling-control metalinsulator transitions (MIT) in transition-metal oxides known as strongly correlated system, disorder has attracted even more attention because not only electronelectron interaction but also disorder are supposed to play fundamentally important roles in the MIT. Altshuler and Aronov [2] studied the effect of electron-electron interaction in a disordered metallic medium, and predicted that the density of states (DOS) near the Fermi level (E F ) shows a singularity of |E − E F | 1/2 and the DOS at E F increases with increasing temperature in proportion to √ T . The theory has been applied to the low temperature conductivity of disordered metals such as disordered Au and Ag films [3], amorphous alloy Ge 1−x Au x [4], and transition metal chalcogenide Ni(S,Se) 2 [5].In a previous work, Sarma et al. [6] have reported photoemission (PES) measurements on B-site disordered perovskites LaNi 1−x M x O 3 (M =Mn and Fe), which show MIT as a function of x, and shown that the disorder affects the DOS near E F in such a way that had been theoretically predicted by Altshuler and Aronov [2]. In a similar B-site substituted transition-metal oxide SrRu 1−x Ti x O 3 , which demonstrates MIT at x ∼ 0.3 (SrRuO 3 is metallic), the depletion of the DOS near E F has shown an unusual |E − E F | 1.2 dependence in both metallic and insulating phases [7]. In addition, although it is believed that a disorder-induced insulator shows a soft Coulomb gap characterized by a (E − E F ) 2 dependence of the DOS near E F [8, 9], the unexpected |E − E F | 3/2 dependence of the DOS near E F related to charge density wave has been observed in insulating BaIrO 3 [10]. It is considered that fine structure in the DOS in the vicinity of E F is sensitive to both the degrees of disorder and electron correlation, and therefore experimental confirmation of a basic theory for disordered electronic system such as the Altshuler-Aronov (AA) theory is necessary for understanding of the DOS singularity. While AA theory makes specific predictions about both E and T dependences, photoelectron spectroscopy has been used only to probe the E dependence with absolutely no reference to the T dependence. Therefore, detai...

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Photoemission and x-ray absorption study of the electronic structure ofSrRu1−xTixO3

Cited by 48 publications

References 37 publications

Electronic structure and stability of hexagonalBa3Ti2RuO9

Electronic structure and stability of hexagonalBa3Ti2RuO9

Single-Particle Excitations under Coexisting Electron Correlation and Disorder: A Numerical Study of the Anderson–Hubbard Model

Critical Test for Altshuler-Aronov Theory: Evolution of the Density of States Singularity in Double PerovskiteSr2FeMoO6with Controlled Disorder

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