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arXiv · 1402.3538

Mechanism of basal-plane antiferromagnetism in the spin-orbit driven iridate Ba2IrO4

Vamshi M. Katukuri·Viktor Yushankhai·Liudmila Siurakshina·Jeroen van den Brink·Liviu Hozoi·Ioannis Rousochatzakis
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Abstract

By ab initio many-body quantum chemistry calculations, we determine the strength of the symmetric anisotropy in the 5$d^5$ j $\approx$ 1/2 layered material Ba$_2$IrO$_4$. While the calculated anisotropic couplings come out in the range of a few meV, orders of magnitude stronger than in analogous 3d transition-metal compounds, the Heisenberg superexchange still defines the largest energy scale. The ab initio results reveal that individual layers of Ba$_2$IrO$_4$ provide a close realization of the quantum spin-1/2 Heisenberg-compass model on the square lattice. We show that the experimentally observed basal-plane antiferromagnetism can be accounted for by including additional interlayer interactions and the associated order-by-disorder quantum-mechanical effects, in analogy to undoped layered cuprates.

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Vamshi M. Katukuri, Viktor Yushankhai, Liudmila Siurakshina, Jeroen van den Brink, Liviu Hozoi, Ioannis Rousochatzakis. 2014-02-14. Mechanism of basal-plane antiferromagnetism in the spin-orbit driven iridate Ba2IrO4. https://doi.org/10.1103/physrevx.4.021051

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