Metal-insulator transitions (MITs) in correlated oxides offer immense potential for next-generation Mottronic devices. However, their integration into practical applications is often hindered by the coupling of MITs with symmetry-lowering structural phase transitions, which limits switching speed and endurance. In this study, we engineered an iso-symmetric MIT on average in epitaxial rutile VO2 thin films via an in-situ nitrogen doping strategy. Nitrogen incorporation effectively suppresses V-V dimerization, enabling an iso-symmetric MIT, while preserving the original crystal symmetry. Furthermore, in-operando time-resolved optical reflectivity measurements revealed a shortened switching time in nitrogen-doped films, highlighting their enhanced performance. Our findings provide critical insights into the underlying mechanisms of MITs and introduce anion doping as a powerful tool for tailoring phase transitions in strongly correlated electron systems. This approach opens new avenues for the development of high-performance electronic and photonic devices.
@article{arxiv.2604.24240,
title = {Nitrogen doping induced metal-insulator transition with iso-symmetric character in rutile VO2},
author = {Baichen Lin and Shanquan Chen and Yubo Zhang and Yangyang Si and Haoliang Huang and Chuanrui Huo and Frans Munnik and Yongqi Dong and Lu You and Jian Shao and Yu-Chieh Ku and Nguyen Nhat Quyen and Aryan Keshri and Zhenlin Luo and Weiwei Zhao and Chun-Fu Chang and Chih-Wei Luo and Sujit Das and Shiqing Deng and Chang-Yang Kuo and Zuhuang Chen},
journal= {arXiv preprint arXiv:2604.24240},
year = {2026}
}