Valence Modifications in Hygroscopic VI 3 Degraded Crystals via Soft X-ray Synchrotron Radiation

High Resolution Image Download MS PowerPoint Slide Among van der Waals crystals, transition metal trihalide VI 3 has drawn attention for its magnetic and orbital properties. However, its chemical instability under ambient conditions makes its exploitation challenging for technological implementation. In this context, here we show how synchrotron radiation soft X-rays induce changes in the valence state of hygroscopic VI 3 crystals aged in high-vacuum conditions. By combining X-ray absorption and X-ray photoemission spectroscopies, we show as-cleaved and aged chemical degradation of the VI 3 crystal surface, with the formation of vanadates, and its valence modifications under high-flux soft X-ray beam exposure, revealing that superficial hygroscopic contamination couples relatively weakly to the crystal surface.