The electronic structure of the high-symmetry perovskite iridate Ba<sub>2</sub>IrO<sub>4</sub>

Moser, Simon; Moreschini, Luca; Ebrahimi, Amirpasha; Piazza, B. Dalla; Isobe, Masaaki; Okabe, Hirotaka; Akimitsu, Jun; Мазуренко, В. В.; Kim, K. S.; Bostwick, Aaron; Rotenberg, Eli; Chang, J.; Rønnow, Henrik M.; Grioni, M.

doi:10.1088/1367-2630/16/1/013008

Cited by 42 publications

(51 citation statements)

References 33 publications

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“…Consequently, tight-binding model calculations were performed using a model for t 2g orbitals which includes the above effects. It gives results in agreement with the angle-resolved photoemission data for the occupied electronic bands [13].…”

Section: Introductionsupporting

confidence: 86%

“…A rather low value of U d ∈ [1.0, 2.0] eV was first suggested by Mazin et al [34], but we argue that a more probable value is U d = 3.0 eV. This value (and J d = 0.6 eV) were used in local density approximation (LDA+U ) computations for Na 2 IrO 3 [35,36] and also for Ba 2 IrO 4 [13]. A similar value of U d = 2.72 eV was obtained by constrained random phase approximation in Na 2 IrO 3 [37].…”

Section: The Hamiltonian Parametersmentioning

confidence: 61%

“…We have adopted the values of in-plane hopping elements (pdσ) and (pdπ) used in Ref. [8] for Sr 2 IrO 4 , and rescaled them (both for in-plane and outof-plane bonds) using Harrison formulas [33] to fit the bond lengths in the structure of Ba 2 IrO 4 (reported by Moser et al [13]). The elements (ppσ) and (ppπ) were taken directly from Ref.…”

Section: The Hamiltonian Parametersmentioning

confidence: 99%

“…Recently mapping of the three-band (d−p) model to a single band was presented and it was shown that further neighbor hopping is necessary to describe the difference between hole and electron doped iridates [11]. The recent experimental evidence seems to support the scenario that Ba 2 IrO 4 is a close realization of spin-orbit Mott insulator rather than a Slater system [12,13], similar to Sr 2 IrO 4 investigated using angle-resolved photoemission [14], op- * This work is dedicated to Professor Józef Spa lek on the occasion of his 70 th birthday.…”

Section: Introductionmentioning

confidence: 99%

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Multibandd−pmodel and self-doping in the electronic structure ofBa2IrO4

Rościszewski

Oleś

2016

Phys. Rev. B

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We introduce and investigate the multiband d − p model describing a IrO4 layer (such as realized in Ba2IrO4) where all 34 orbitals per unit cell are partly occupied, i.e., t2g and eg orbitals at iridium and 2p orbitals at oxygen ions. The model takes into account anisotropic iridium-oxygen d − p and oxygen-oxygen p − p hopping processes, crystal-field splittings, spin-orbit coupling, and the on-site Coulomb interactions, both at iridium and at oxygen ions. We show that the predictions based on assumed idealized ionic configuration (with n0 = 5 + 4 × 6 = 29 electrons per IrO4 unit) do not explain well the independent ab initio data and the experimental data for Ba2IrO4. Instead we find that the total electron density in the d − p states is smaller, n = 29 − x < n0 (x > 0). When we fix x = 1, the predictions for the d − p model become more realistic and weakly insulating antiferromagnetic ground state with the moments lying within IrO2 planes along (110) direction is found, in agreement with experiment and ab initio data. We also show that: (i) holes delocalize over the oxygen orbitals and the electron density at iridium ions is enhanced, hence (ii) their eg orbitals are occupied by more than one electron and have to be included in the multiband d − p model describing iridates.

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Section: Introductionsupporting

confidence: 86%

Section: The Hamiltonian Parametersmentioning

confidence: 61%

Section: The Hamiltonian Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multibandd−pmodel and self-doping in the electronic structure ofBa2IrO4

Rościszewski

Oleś

2016

Phys. Rev. B

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“…20 In contrast, a recent angle-resolved photoemission measurement suggests that the data are consistent with a Mott scenario rather than a Slater scenario. 21 Under such circumstances, it may make sense to study elementary excitations from the intermediate coupling scheme based on the itinerant electron picture. In this paper, introducing the multi-orbital Hubbard model to describe the system, we calculate the particle-hole Green's function within the Hartree-Fock approximation (HFA) and the random phase approximation (RPA).…”

mentioning

confidence: 99%

Interplay between Hund’s Coupling and Spin–Orbit Interaction on Elementary Excitations in Sr₂IrO₄

Igarashi

Nagao

2014

J. Phys. Soc. Jpn.

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We study the elementary excitations in 5d transition metal oxide Sr2IrO4 by calculating the particle-hole Green's function within the random phase approximation on an antiferromagnetic ground state in the two-dimensional multi-orbital Hubbard model. The obtained magnetic excitations of bound states show a characteristic dispersion in consistent with the experiments. In addition, two new types of excitations are found due to the interplay between spin-orbit interaction and Hund's coupling: a magnetic excitation as a bound state, which has energy gap at the Γ point, and an exciton as a resonant mode in the continuum of electron-hole pair creation.Electron correlation effects on transition metals and their compounds have attracted much interest since the discovery of high-T C cuprate superconductors. In the 3d transition metal ions, the spin orbit interaction (SOI) plays a minor role on the electronic structures, since it is usually much smaller than the on-site Coulomb interaction and the crystal field splitting. In the 5d transition metal ions, however, the SOI is one order of magnitude larger than that of the 3d systems while the Coulomb interaction becomes weaker due to the extended nature of the 5d electrons. Accordingly, the interplay between the electron correlation and the SOI is expected to bring about new intriguing phenomena. For this reason, much attention has recently been paid to Ir oxides such as Sr 2 IrO 4 1-8 and Na 2 IrO 3 . [9][10][11][12] In particular, we focus on Sr 2 IrO 4 , which consists of two-dimensional IrO 2 layers showing structural similarity to the parent compound of high-T C cuprate La 2 CuO 4 , and exhibits a canted antiferromagnetic (AFM) order below 230 K. 1-3 The energy of the e g orbitals is estimated about 2 eV higher than that of the t 2g orbitals due to the large crystal field. Five 5d electrons are occupied per Ir atom, and one hole is sitting in the t 2g orbitals. Since the hole states have an effective orbital angular momentum ℓ equal to −1, the lowest-energy states on the localized electron picture are doubly degenerate with the effective total angular momentum j eff = 1 2 under the SOI: 13,14 |φ ± = 1 √ 3 (|yz, ∓σ ± i|zx, ∓σ ± |xy, ±σ ), where yz, zx, and xy designate t 2g orbitals, and spin component σ =↑. By introducing the isospin operators acting on these states, the system is mapped onto the Heisenberg model, from which an insulating AFM phase is derived, consistent with the experiments. 1-3 Furthermore, it has been pointed out that the small anisotropic terms emerge in addition to the isotropic term, when Hund's coupling is taken into account in the second-order process in the strong coupling expansion. 15,16 Recently, resonant inelastic x-ray scattering (RIXS) experiment at the Ir L edge has detected the excitation spectra, 17 whose low energy part follows the dispersion relation similar to the spin wave in the Heisenberg model on a square lattice. A notable point is that the excitation energy at the M point is nearly half of that at the X point, in contrast to t...

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An experimentalist's guide to the matrix element in angle resolved photoemission

Moser

2017

Journal of Electron Spectroscopy and Related Phenomena

156

136

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Angle resolved photoemission spectroscopy (ARPES) is commonly known as a powerful probe of the one-electron removal spectral function in ordered solid state. With increasing efficiency of light sources and spectrometers, experiments over a wide range of emission angles become more and more common. Consequently, the angular variation of ARPES spectral weight-often times termed "matrix element effect"-enters as an additional source of information. In this tutorial, we develop a simple but instructive free electron final state approach based on the three-step model to describe the intensity distribution in ARPES. We find a compact expression showing that the ARPES spectral weight of a given Bloch band is essentially determined by the momentum distribution (the Fourier transform) of its associated Wannier orbital-times a polarization dependent pre-factor. While the former is giving direct information on the symmetry and shape of the electronic wave function, the latter can give rise to surprising geometric effects. We discuss a variety of modern and instructive experimental showcases for which this simplistic formalism works astonishingly well and discuss the limits of this approach.

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The electronic structure of the high-symmetry perovskite iridate Ba₂IrO₄

Cited by 42 publications

References 33 publications

Multibandd−pmodel and self-doping in the electronic structure ofBa2IrO4

Multibandd−pmodel and self-doping in the electronic structure ofBa2IrO4

Interplay between Hund’s Coupling and Spin–Orbit Interaction on Elementary Excitations in Sr₂IrO₄

An experimentalist's guide to the matrix element in angle resolved photoemission

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The electronic structure of the high-symmetry perovskite iridate Ba2IrO4

Cited by 42 publications

References 33 publications

Multibandd−pmodel and self-doping in the electronic structure ofBa2IrO4

Multibandd−pmodel and self-doping in the electronic structure ofBa2IrO4

Interplay between Hund’s Coupling and Spin–Orbit Interaction on Elementary Excitations in Sr2IrO4

An experimentalist's guide to the matrix element in angle resolved photoemission

Contact Info

Product

Resources

About

The electronic structure of the high-symmetry perovskite iridate Ba₂IrO₄

Interplay between Hund’s Coupling and Spin–Orbit Interaction on Elementary Excitations in Sr₂IrO₄