Pressure‐Induced Metallization and Isostructural Transitions in 3R‐MoS₂

Abstract At ambient conditions 3R‐polytypes of transition metal dichalcogenides (TMDs) demonstrate fascinating properties because of their unique layer stacking. Understanding the structure‐property relationship is essential for the realization of their use in spintronic, valleytronic, and optoelectronic applications. Herein, after the high pressure‐temperature synthesis of 3R‐MoS₂ in a large volume cubic press, a concomitant experimental and theoretical high‐pressure study of 3R‐MoS₂ is reported, leading to the discovery of pressure‐induced reversible isostructural phase transitions without symmetry breaking. Concurrent with the isostructural transitions, a semiconductor‐to‐metal transition is observed, owing to strong interlayer interaction and charge redistribution across the van der Waals gap under pressure. The pressure‐induced enhancement of interlayer interactions together with the robust intrinsic layer stacking in 3R‐MoS₂ prevent the layers from sliding under pressure and hinder a corresponding volume collapse. This study on continuous pressure‐tuning of crystal and electronic structure in 3R‐MoS₂ will play a vital role in developing the next‐generation devices involving coupling of structural, optical, and electrical properties of 3R‐polytypes of TMDs and other layered materials.