Nitrogen doping induced metal-insulator transition with iso-symmetric character in rutile VO2

TL;DR

This study demonstrates that nitrogen doping in rutile VO2 thin films induces an iso-symmetric metal-insulator transition, suppressing structural changes and enhancing switching speed for potential electronic applications.

Contribution

We engineered an iso-symmetric MIT in VO2 via nitrogen doping, preserving crystal symmetry and improving transition speed, offering new control over phase transitions in correlated oxides.

Findings

Nitrogen doping suppresses V-V dimerization in VO2.

Nitrogen-doped VO2 exhibits a shortened switching time.

The approach enables phase transition control without symmetry breaking.

Abstract

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.