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arXiv · 1703.09051

Anisotropic exchange and spin-wave damping in pure and electron-doped Sr$_2$IrO$_4$

Davide Pincini·James G. Vale·Christian Donnerer·Alberto de la Torre·Emily C. Hunter·Robin Perry·Marco Moretti Sala·Felix Baumberger·Desmond F. McMorrow
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Abstract

The collective magnetic excitations in the spin-orbit Mott insulator (Sr$_{1-x}$La$_x$)$_2$IrO$_4$ ($x=0,\,0.01,\,0.04,\, 0.1$) were investigated by means of resonant inelastic x-ray scattering. We report significant magnon energy gaps at both the crystallographic and antiferromagnetic zone centers at all doping levels, along with a remarkably pronounced momentum-dependent lifetime broadening. The spin-wave gap is accounted for by a significant anisotropy in the interactions between $J_\text{eff}=1/2$ isospins, thus marking the departure of Sr$_2$IrO$_4$ from the essentially isotropic Heisenberg model appropriate for the superconducting cuprates.

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Davide Pincini, James G. Vale, Christian Donnerer, Alberto de la Torre, Emily C. Hunter, Robin Perry, Marco Moretti Sala, Felix Baumberger, Desmond F. McMorrow. 2017-03-27. Anisotropic exchange and spin-wave damping in pure and electron-doped Sr$_2$IrO$_4$. https://doi.org/10.1103/physrevb.96.075162

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