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تسجيل مستخدم جديدMagnetism in artificial Ruddlesden-Popper iridates leveraged by structural distortions
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We report on the tuning of magnetic interactions in superlattices composed of single and bilayer SrIrO$_3$ inter-spaced with SrTiO$_3$. Magnetic scattering shows predominately $c$-axis antiferromagnetic orientation of the magnetic moments for the bilayer justifying these systems as viable artificial analogues of the bulk Ruddlesden-Popper series iridates. Magnon gaps are observed in both superlattices, with the magnitude of the gap in the bilayer being reduced to nearly half that in its bulk structural analogue, Sr$_3$Ir$_2$O$_7$. We assign this to modifications in the anisotropic exchange driven by bending of the $c$-axis Ir-O-Ir bond and subsequent local environment changes, as detected by x-ray diffraction and modeled using spin wave theory. These findings explain how even subtle structural modulations driven by heterostructuring in iridates are leveraged by spin orbit coupling to drive large changes in the magnetic interactions.
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The goal of this work is studying the evolution of thermoelectric transport across the members of the Ruddlesden-Popper series iridates Srn+1IrnO3n+1, where a metal-insulator transition driven by bandwidth change occurs, from the strongly insulating
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In this study, we systematically investigate 3D momentum($hbar k$)-resolved electronic structures of Ruddlesden-Popper-type iridium oxides Sr$_{n+1}$Ir$_n$O$_{3n+1}$ using soft-x-ray (SX) angle-resolved photoemission spectroscopy (ARPES). Our results
provide direct evidence of an insulator-to-metal transition that occurs upon increasing the dimensionality of the IrO$_2$-plane structure. This transition occurs when the spin-orbit-coupled $j_{rm eff}$=1/2 band changes its behavior in the dispersion relation and moves across the Fermi energy. In addition, an emerging band along the $Gamma$(0,0,0)-R($pi$,$pi$,$pi$) direction is found to play a crucial role in the metallic characteristics of SrIrO$_3$. By scanning the photon energy over 350 eV, we reveal the 3D Fermi surface in SrIrO$_3$ and $k_z$-dependent oscillations of photoelectron intensity in Sr$_3$Ir$_2$O$_7$. In contrast to previously reported results obtained using low-energy photons, folded bands derived from lattice distortions and/or magnetic ordering make significantly weak (but finite) contributions to the $k$-resolved photoemission spectrum. At the first glance, this leads to the ambiguous result that the observed $k$-space topology is consistent with the unfolded Brillouin zone (BZ) picture derived from a non-realistic simple square or cubic Ir lattice. Through careful analysis, we determine that a superposition of the folded and unfolded band structures has been observed in the ARPES spectra obtained using photons in both ultraviolet and SX regions. To corroborate the physics deduced using low-energy ARPES studies, we propose to utilize SX-ARPES as a powerful complementary technique, as this method surveys more than one whole BZ and provides a panoramic view of electronic structures.
We study the optical properties of the Ruddlesden-Popper series of iridates Sr$_{n+1}$Ir$_n$O$_{3n+1}$ ($n$=1, 2 and $infty$) by solving the Bethe-Salpeter equation (BSE), where the quasiparticle (QP) energies and screened interactions $W$ are obtain
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We study the correlated electronic structure of single-layer iridates based on structurally-undistorted Ba$_2$IrO$_4$. Starting from the first-principles band structure, the interplay between local Coulomb interactions and spin-orbit coupling is inve
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Scanning transmission electron microscopy in combination with electron energy-loss spectroscopy is used to study LaNiO3/LaAlO3 superlattices grown on (La,Sr)AlO4 with varying single-layer thicknesses which are known to control their electronic proper
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