Mechanical Bending Strain-Actuated Modulation of Metal–Insulator Transition Temperature in Flexible Epitaxial V₂O₃ Films

In the era of the Internet of Things, flexible oxide electronics have been intensely investigated due to their unique advantages in portability, pliability, and stability. Among various oxide material systems, correlated electron materials (CEMs) have attracted significant attention, because they can display a broad range of intriguing phenomena such as colossal magnetoresistance, high-temperature superconductivity, and a metal–insulator transition (MIT). Tuning the electronic properties of CEMs featuring MIT behavior through the use of external stimuli is a prerequisite for developing CEM-based devices. Here we report a strong mechanical bending strain-actuated modulation of the MIT temperature ( T MIT ) in flexible V 2 O 3 /mica heterostructures. The epitaxial V 2 O 3 thin films on flexible mica substrates were prepared by a pulsed-laser deposition (PLD) technique. Depending on the growth conditions, various lattice parameter ratios ( c / a ) and distinct different electronic transport properties were found in a series of V 2 O 3 /mica films. For the V 2 O 3 films with c / a = 2.84 and 2.82, MIT behaviors were observed at T MIT ≈ 155 K and ≈ 172 K, respectively. Mechanical bending strain imposed from buckling the mica substrates was shown to remarkably modulate the T MIT (Δ T MIT ≈ 30 K) in these flexible V 2 O 3 films. Additionally, we note that the bending response of T MIT in the V 2 O 3 films relies on the applied bending strain direction. Bending cyclic tests manifest a good repetition of the experimental results and superior mechanical durability in flexible V 2 O 3 films. The present work is highly instructive for flexible electronic device applications and provides an alternative platform for studying MIT behaviors of the CEMs in general.