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arXiv · 1706.10103

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

H. Gretarsson·J. Sauceda·N. H. Sung·M. Höppner·M. Minola·B. J. Kim·B. Keimer·M. Le Tacon
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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.

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H. Gretarsson, J. Sauceda, N. H. Sung, M. Höppner, M. Minola, B. J. Kim, B. Keimer, M. Le Tacon. 2017-09-07. Raman scattering study of vibrational and magnetic excitations in Sr$_{2-x}$La$_x$IrO$_4$. https://doi.org/10.1103/physrevb.96.115138

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