2025/12/13 by Yuan-Shan Zhang, Zhang, Yuan-Shan, Yang Zi-chen +11
Chemistry · Materials Science · #2D Materials and Applications #Advanced Physical and Chemical Molecular Interactions #Chemical and Physical Properties of Materials #FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2512.12439
openalex publication_date 2025/12/13 · openalex created_date 2025/12/17 · openalex updated_date 2026/07/28
Ta2NiSe5 continues to draw interest for its 326 K phase transition, whose dual electronic and structural nature reflects a complex interplay of electron-hole (excitonic) and electron-lattice interactions. Most studies that have attempted to decipher the relative importance of these interactions, particularly through charge transfer, have been limited to bulk samples. We utilized a thin-flake approach to modify the excitonic interactions in Ta2NiSe5 via an underlying film of Au. Using polarized Raman spectroscopy, we found that four layers of Ta2NiSe5 supported on conducting Au show a transition temperature that is both reduced by over 100 K and broadened due to an interfacial charge gradient effect, manifesting the presence of excitonic interactions. In contrast, four layers of Ta2NiSe5 supported on insulating Al2O3 show nearly bulk-like properties. We also report the development of an all-dry exfoliation and transfer protocol that generalizes substrate engineering for strongly correlated van der Waals materials.