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arXiv · 1607.02981

Compass Impurity Model of Tb Substitution in Sr2IrO4

Long Zhang·Fa Wang·Dung-Hai Lee
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Abstract

We show that upon Tb substitution the interaction between the magnetic moments on the impurity Tb$^{4+}$ ion and its surrounding Ir$^{4+}$ ions is described by a "compass" model, i.e., Ising-like interaction favoring the magnetic moments across each bond to align along the bond direction. Such interaction nucleates quenched magnetic vortices near the impurities and drives a reentrant transition out of the antiferromagnetic ordered phase at low temperatures hence quickly suppresses the Néel temperature consistent with the experiment [Phys. Rev. B \textbf{92}, 214411 (2015)]. As a by-product, we propose that the compass model can be realized in ordered double perovskites composed of the spin-orbital-coupled $d^{5}$ ions and the half-closed-shell $f^{7}$ ions.

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Long Zhang, Fa Wang, Dung-Hai Lee. 2016-10-22. Compass Impurity Model of Tb Substitution in Sr2IrO4. https://doi.org/10.1103/physrevb.94.161118

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