Nanoscale Structural Evolution of Electrically Driven Insulator to Metal Transition in Vanadium Dioxide

We report the evolution of local structural of tensile strained vanadium dioxide thin films during an electrically driven insulator to metal transition by nanoscale hard X-ray diffraction. Evaluation of the Bragg diffraction intensity reveals a narrow metallic filament with rutile structure to be the dominant conduction pathway for the electrically driven insulator to metal transition, while the remainder of the channel area remained the monoclinic M1 phase. The filament dimensions were estimated using simultaneous electrical probing and nanoscale X-ray diffraction measurements. Analysis revealed that the width of the conducting channel can be tuned externally using resistive loads in series allowing for the manipulation of the M1/R phase ratio in the phase coexistence regime.