Structural transitions of superconducting quasi-1D materials under high pressure using combined XAS and XRD

Recently, the quasi-1D materials (MSe4)2I (M=Ta and Nb) are found to transform into the hybrid crystalline/amorphous structure under pressure, and superconductivity is closely related to the disorder phase. However, the order-disorder structural pathway and the nature of dense disorder phase under pressure remains poorly understood. X-ray absorption spectroscopy has been demonstrated as efficient tool for probing the local structural changes of disorder materials under pressure. Here, we propose to systematically study the crystalline phase transitions, order-disorder transitions of (MSe4)2I (M=Ta and Nb) under pressure using the combined in situ XAS and XRD at room temperature. Through this proposal, we hope to improve our understanding of structure pathway and local structure changes of the quasi-1D materials under pressure and provide a key insight into the correlation between physical properties and disordered structure.