Diverse Edge and Excitonic States of Ta2Ni3Te5 Nanoribbons and Monolayer: Implications for Nanoelectronics

Abstract

Ta2Ni3Te5, a layered transition-metal chalcogenide with quasi-one-dimensional electronic states, exhibits a rich variety of topological and correlation-driven phenomena. Using first-principles calculations, we investigate Ta2Ni3Te5 nanoribbons and demonstrate tunable electronic and magnetic properties, ranging from metallic, semimetallic, and semiconducting behavior to ferromagnetic and antiferromagnetic ordering. These properties can be controlled through the edge termination (Ni or Ta), ribbon width, and H/F passivation. Furthermore, GW and Bethe–Salpeter equation (BSE) calculations, corroborated by a meta-generalized-gradient-approximation (meta-GGA)-based modified BSE approach, indicate that monolayer Ta2Ni3Te5 is an excitonic insulator, with the binding energy of the lowest-energy exciton exceeding the fundamental band gap. These findings highlight the strong potential of Ta2Ni3Te5-based nanostructures for applications in nanoelectronics, spintronics, and quantum technologies.