Enhanced 1T′‐Phase Stabilization and Chemical Reactivity in a MoTe 2 Monolayer through Contact with a 2D Ca 2 N Electride

Among the widely studied 2D transition metal dichalcogenides (TMDs), MoTe 2 has attracted special interest for phase‐change applications due to its small 2H‐1T′ energy difference, yet a large scale phase transition without structural disruption remains a significant challenge. Recently, an interesting long‐range phase engineering of MoTe 2 has been realized experimentally by Ca 2 N electride. However, the interface formed between them has not been well understood, and moreover, it remains elusive how the presence of Ca 2 N would affect the basal plane reactivity of MoTe 2 . To address this, we performed density functional theory (DFT) calculations to investigate the potential of tuning the phase stability and chemical reactivity of a MoTe 2 monolayer via interacting with Ca 2 N to form a van der Walls heterostructure. We found that the contact nature at the 2H‐MoTe 2 /Ca 2 N interface is Schottky‐barrier‐free, allowing for the spontaneous electron transfer from Ca 2 N to 2H‐MoTe 2 to make it strongly n‐type doped. Moreover, Ca 2 N doping significantly lowers the energy of 1T′‐MoTe 2 and dynamically triggers the 2H‐to‐1T′ transformation. The Ca 2 N‐induced phase modulation can also be applied to tune the phase energetics of MoS 2 and MoSe 2 . Furthermore, using H adsorption as the testing ground, we also find that the H binding on the basal plane of MoTe 2 is enhanced after forming heterostructure with Ca 2 N, potentially providing basis for surface modification and other related catalytic applications.