Polymorphism of low-dimensional material with ternary composition chalcogenide Ta2Ni3Se8

In this study, the polymorphism of Ta2Ni3Se8, a three-component one-dimensional chalcogenide material, was discovered. It was confirmed through X-ray diffraction and transmission electron microscopy analyses that the newly identified tetragonal phase of the compound (T-Ta2Ni3Se8) had a different crystal structure from the previously reported orthorhombic phase (O-Ta2Ni3Se8). Conventional O-Ta2Ni3Se8 is a semiconductor material with ambipolar characteristics, whereas T-Ta2Ni3Se8 showed a metallic characteristic in which the electrical resistance slightly increased as the temperature increased. The change in electrical properties due to the variation in lattice isotropy according to the transformation of the crystal system (orthorhombic to tetragonal) is expected to be an important starting point for polymorphism studies of multi-component low-dimensional materials in the future. (C) 2022 Elsevier B.V. All rights reserved.