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arXiv · 1508.05729

Jahn-Teller induced nematic orbital order in tetragonal Sr$_2$VO$_4$

J. Teyssier·E. Giannini·A. Stucky·R. Cerný·M. V. Eremin·D. van der Marel
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Abstract

Using high resolution X-Ray diffraction (XRD) on high purity powders, we resolved the structure and $ab$ symmetry of the intriguing compound \svo$ $ from room temperature down to 20 K to an unprecedented level of accuracy. Upon cooling, this new set of data unambiguously reveals a second order phase transition lowering the symmetry from tetragonal to orthorhombic at a temperature $T_{c2}=136$ K. The observation of an orthorhombic distortion of the $ab$-plane is attributed to nematic phase formation supported by local Jahn-Teller (JT) dynamical instability. At $T_{N}=105$ K, spins order and at $T_{c1}=100$ K the tetragonal structure is recovered with an elongated c-axis.

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J. Teyssier, E. Giannini, A. Stucky, R. Cerný, M. V. Eremin, D. van der Marel. 2015-08-24. Jahn-Teller induced nematic orbital order in tetragonal Sr$_2$VO$_4$. https://doi.org/10.1103/physrevb.93.125138

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