Importance of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mrow><mml:mn>2</mml:mn><mml:mi>g</mml:mi></mml:mrow></mml:msub><mml:mtext>−</mml:mtext><mml:msub><mml:mi>e</mml:mi><mml:mi>g</mml:mi></mml:msub></mml:mrow></mml:math>hybridization in transition metal oxides

Landron, Sylvain; Lepetit, Marie-Bernadette

doi:10.1103/physrevb.77.125106

Cited by 66 publications

(58 citation statements)

References 19 publications

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“…The e ge g couplings, for instance, were found to be important in trigonally distorted 3d 5 compounds. 52 Our data in Table II, showing that with trigonal distortions the a 1g -e g splittings decrease (as∆ <∆ 0 ), qualitatively confirm the quantum chemistry results of Landron and Lepetit, i.e., in the presence of trigonal squashing the e g levels are energetically favored as compared to the a 1g states, in contrast to naive expectations based on one-electron crystal-field theory. Obviously, for 5d oxides, the t 2g -e g couplings are further enhanced by the strong SOI's.…”

supporting

confidence: 86%

Longer-range lattice anisotropy strongly competing with spin-orbit interactions in pyrochlore iridates

Hozoi¹,

Gretarsson²,

Clancy³

et al. 2014

Phys. Rev. B

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In the search for topological phases in correlated electron systems, materials with 5d transitionmetal ions, in particular, the iridium-based pyrochlores A2Ir2O7, provide fertile grounds. Several novel topological states have been predicted but the actual realization of such states is believed to critically depend on the strength of local potentials arising from distortions of the IrO6 cages. We test this hypothesis by measuring with resonant inelastic x-ray scattering the electronic level splittings in the A=Y, Eu systems, which we show to agree very well with ab initio quantum chemistry electronic-structure calculations for the series of materials with A=Sm, Eu, Lu, and Y. We find, however, that not distortions of the IrO6 octahedra are the primary source for quenching the spin-orbit interaction, but longer-range lattice anisotropies which inevitably break the local cubic symmetry.

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supporting

confidence: 86%

Longer-range lattice anisotropy strongly competing with spin-orbit interactions in pyrochlore iridates

Hozoi¹,

Gretarsson²,

Clancy³

et al. 2014

Phys. Rev. B

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“…The same angle change can also be seen in RCrO 3 . Landron and Lepetit 19 have shown that the intrasite hybridization between t and e orbitals is highly sensitive to the angle ␤ ͑they have defined the trigonal distortion of an octahedron by a different angle͒. In our case, the intrasite t-e hybridization vanishes for ␤ = 90°.…”

Section: Resultsmentioning

confidence: 53%

Intrinsic structural distortion and superexchange interaction in the orthorhombic rare-earth perovskitesRCrO3

et al. 2010

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High-resolution neutron powder diffraction has been applied to determine the structural evolution in the orthorhombic perovskite RCrO 3 family. The structural distortions observed have been found to be closely related to the dramatic variation in the magnetic ordering temperature T N . In addition to the reduction in the orbital overlap integral that can account for the change in T N in the RFeO 3 family, the effect of t-e hybridization due to the structural distortions are responsible for the dramatic change in T N across the RCrO 3 family.

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“…6, we show the ∆-dependence of T c at U = 4 and 6 eV for unhydrate and hydrate systems, respectively. Note that the cluster calculation using quantum chemical ab-initio methods suggests U = 4.1 ∼ 4.8 eV [34]. In both cases, T c is almost zero if we drop shear phonons (b 1 = b 2 = 0).…”

Section: Numerical Resultsmentioning

confidence: 89%

“…Here, we regard ∆ as variable. Equations (33) and (34) are shown in Fig. 4 (a) and (b), respectively.…”

Section: Derivation Of Gap Equationmentioning

confidence: 99%

s-wave superconductivity due to Suhl-Kondo mechanism inNaxCoO2⋅yH2

Yada

Kontani

2008

Phys. Rev. B

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To study the electron-phonon mechanism of superconductivity in NaxCoO2 · yH2O, we perform semiquantitative analysis of the electron-phonon interaction (EPI) between relevant optical phonons (breathing and shear phonons) and t2g electrons (a1g and e ′ g electrons) in the presence of trigonal distortion. We consider two kinds of contributions to the EPI; the EPI originating from the Coulomb potential of O ions and that originating from the d-p transfer integral between Co and O in CoO6 octahedron. We find that the EPI for shear phonons, which induces the interorbital hopping of electrons, is large in NaxCoO2 · yH2O because of the trigonal distortion of CoO2 layer. For this reason, Tc for s-wave pairing is prominently enlarged owing to interorbital hopping of Cooper pairs induced by shear phonons, even if the top of e ′ g electron band is close to but below the Fermi level as suggested experimentally. This mechanism of superconductivity is referred to as the valenceband Suhl-Kondo (SK) mechanism. Since the SK mechanism is seldom damaged by the Coulomb repulsion, s-wave superconductivity is realized irrespective of large Coulomb interaction U ∼ 5 eV at Co sites. We also study the oxygen isotope effect on Tc, and find that it becomes very small due to strong Coulomb interaction. Finally, we discuss the possible mechanism of anisotropic s-wave superconducting state in NaxCoO2 · yH2O, resulting from the coexistence of strong EPI and the antiferromagnetic fluctuations.

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Importance oft2g−eghybridization in transition metal oxides

Abstract: The crucial importance of the t 2g -e g hybridization in transition metal oxides

Cited by 66 publications

References 19 publications

Longer-range lattice anisotropy strongly competing with spin-orbit interactions in pyrochlore iridates

Longer-range lattice anisotropy strongly competing with spin-orbit interactions in pyrochlore iridates

Intrinsic structural distortion and superexchange interaction in the orthorhombic rare-earth perovskitesRCrO3

s-wave superconductivity due to Suhl-Kondo mechanism inNaxCoO2⋅yH2

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