Understanding the structural transition of TiSe2 monolayer from coordination chemistry

Monolayer TiSe2 exhibits a low-temperature phase transition whose underlying mechanism has attracted increasing attention. Moreover, reproducing the experimentally observed band structure in the normal phase has posed a significant challenge for first-principles studies. To address these issues, several approaches beyond standard density functional theory have recently been explored [Pashov et al., npj Comput. Mater. 11, 152 (2025)]. In this work, we highlight the role of coordination interactions in TiSe2. By applying principles of coordination chemistry, we propose a unified framework that accounts for both its phase transition and its unusual band structure. These insights provide a broader and more cohesive understanding of structural transitions in transition-metal dichalcogenides.