Raman scattering study of vibrational and magnetic excitations in Sr${}_{2-x}$La${}_x$IrO${}_4$

Abstract

We have measured the doping and temperature dependence of lattice vibrations and magnetic excitations in the prototypical doped spin-orbit Mott insulator Sr${}_{2-x}$La${}_x$IrO${}_4$ (x=0, 0.015, and 0.10). Our findings show that the pseudospin-lattice coupling -- responsible for the renormalization of several low energy phonon modes -- is preserved even when long-range magnetic order is suppressed by doping. In our most highly doped sample, the single magnon (Gamma-point) excitation disappears while the two-magnon mode softens and becomes heavily damped. Doping induced electron-phonon coupling is also observed in a higher energy phonon mode. We observe two different electron-phonon interaction channels, which provide evidence of the coexistence of fluctuating magnetic moments and mobile carriers in doped iridates.

9 pages, 9 figures

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• Twisted Hubbard Model for Sr2IrO4: Magnetism and Possible High Temperature Superconductivity
• Fermi Arcs in a Doped Pseudospin-1/2 Heisenberg Antiferromagnet
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• Odd-parity triplet superconductivity in multi-orbital materials with strong spin-orbit coupling: applications to doped Sr2IrO4
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Cited by in corpus (16)

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• Square Lattice Iridates
• Spectroscopic evidence for electron-boson coupling in electron-doped Sr${}_2$IrO${}_4$
• Compressive-strain induced enhancement of exchange interactions and short-range magnetic order in Sr${}_2$IrO${}_4$ investigated by Raman spectroscopy
• Nanoscale Sr${}_2$IrO${}_4$ Freestanding Thin-Films for Flexible Electronics
• Decoupling of static and dynamic criticality in a driven Mott insulator
• Pseudospin-lattice coupling and electric control of the square-lattice iridate Sr2IrO4
• Strong electron-phonon coupling and enhanced phonon Grüneisen parameters in valence-fluctuating metal EuPd${}_2$Si${}_2$
• Linear scaling relationship of Néel temperature and dominant magnons in pyrochlore ruthenates
• Single crystal growth of iridates without platinum impurities
• Magnetic order, disorder, and excitations under pressure in the Mott insulator Sr${}_2$IrO${}_4$
• Spin-orbit excitons in a correlated metal: Raman scattering study of Sr2RhO4
• Magneto-synthesis effect on magnetic order, phonons, and magnons in single-crystal Sr${}_2$IrO${}_4$
• Evolution of the spectral lineshape at the magnetic transition in Sr2IrO4 and Sr3Ir2O7
• Absence of temperature-dependent phonon anomalies in Sr2IrO4 and Sr3Ir2O7
• Non-Loudon-Fleury Raman scattering in spin-orbit coupled Mott insulators