Structural study of quasi-one-dimensional vanadium pyroxene LiVSi₂O₆ single crystals

Single crystals of quasi-one-dimensional vanadium pyroxene LiVSi₂O₆ were synthesized and the crystal structures at 293 K and 113 K were studied using X-ray diffraction experiments. We found a structural phase transition from the room-temperature crystal structure with space group C2/c to a low-temperature structure with space group P2₁/c, resulting from a rotational displacement of SiO₄ tetrahedra. The temperature dependence of magnetic susceptibility shows a broad maximum around 116 K, suggesting an opening of the Haldane gap expected for one-dimensional antiferromagnets with S=1. However, an antiferromagnetic long-range order was developed below 24 K, probably caused by a weak inter-chain magnetic coupling in the compound. - Graphical abstract: Low temperature crystal structure of LiVSi₂O₆ and an orbital arrangement within the V-O zig-zag chain along the c-axis. - Highlights: • A low temperature structure of LiVSi₂O₆ was determined by single crystal X-ray diffraction measurements. • The origin of the structural transition is a rotational displacement of SiO₄ tetrahedra. • The uniform orbital overlap in the V-O zigzag chain makes the system a quasi one-dimensional antiferromagnet.