Direct Observation of Magnetic Frustration via Bond-directional Interactions in a Honeycomb Lattice Iridate Na$_{2}$IrO$_{3}$
ORAL
Abstract
Despite its long-range zigzag magnetic ground state, the honeycomb Na2IrO3 is considered as a model system for approaching a Kitaev quantum spin liquid due to a proposed bond-directional magnetic frustration. Using resonant x-ray magnetic scattering, we find direct evidence of this frustration and follow its temperature dependence. We observe that three zigzag magnetic states with short-range correlation are displayed in the diffuse magnetic peaks as a function of scattering geometry up to 6T$_{\mathrm{N}}$. Each zigzag state breaks C3 symmetry individually, but the simultaneous C3 rotation in both real and spin spaces remains invariant as consequence of the distinct magnetic anisotropies tied to three Ir-Ir bonds in the lattice. This result confirms the dominant role of the bond-directional interactions in the frustration.
*Work in the Materials Science Division at Argonne National Laboratory supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Division of Materials Science and Engineering.
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Authors
Sae Hwan Chun
Materials Science Division, Argonne National Laboratory
H. Zheng
Materials Science Division, Argonne National Laboratory
C. Stoumpos
Materials Science Division, Argonne National Laboratory
C. Malliakas
Materials Science Division, Argonne National Laboratory
J.F. Mitchell
Materials Science Division, Argonne National Laboratory
Jong-Woo Kim
Advanced Photon Source, Argonne National Laboratory
Jungho Kim
Advanced Photon Source, Argonne National Laboratory
Y. Choi
Advanced Photon Source, Argonne National Laboratory
T. Gog
Advanced Photon Source, Argonne National Laboratory
Kavita Mehlawat
Indian Institute of Science Education and Research Mohali
Yogesh Singh
Indian Institute of Science Education and Research Mohali
A. Al-Zein
European Synchrotron Radiation Facility
M. Morreti Sala
European Synchrotron Radiation Facility
M. Krisch
European Synchrotron Radiation Facility
J. Chaloupka
Central European Institute of Technology, Masaryk University
