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arXiv · 2511.06366

Linear tetramer formation in nonmagnetic pyrochlore niobate

Shota Nishida·Shunsuke Kitou·Shingo Toyoda·Yuiga Nakamura·Yusuke Tokunaga·Taka-hisa Arima
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Abstract

We investigate displacive short-range order in pyrochlore Y2Nb2O7, which exhibits a nonmagnetic insulating state despite the presence of formally tetravalent Nb4+ (S = 1/2) ions on the pyrochlore network. Synchrotron x-ray diffraction on a single crystal reveals a characteristic x-ray diffuse scattering (XDS) pattern primarily around q = {0.5, 0.5, 2}. Reverse Monte Carlo (RMC) simulations uncover local Nb displacements along the <111> axes, leading to the formation of linear Nb4 tetramers. Our findings highlight a crucial role of molecular orbital degrees of freedom in stabilizing the nonmagnetic insulating state. This study demonstrates that RMC analysis of XDS provides a powerful approach for elucidating short-range correlations and the underlying mechanisms governing the physical properties of crystalline materials.

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Shota Nishida, Shunsuke Kitou, Shingo Toyoda, Yuiga Nakamura, Yusuke Tokunaga, Taka-hisa Arima. 2025-11-09. Linear tetramer formation in nonmagnetic pyrochlore niobate. https://doi.org/10.1103/qq1h-lgbc

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