研究目的
To demonstrate a pressure-induced transition in a c-axis oriented vanadium sesquioxide (V2O3) thin film from a strongly correlated metal to a Mott insulator in a submicrometric region by inducing a local stress using contact atomic force microscopy.
研究成果
The study successfully demonstrated a reversible metal-insulator transition in a V2O3 thin film induced by local stress using C-AFM. The transition is attributed to the modification of the electron density of states and lattice degrees of freedom due to changes in the c/a ratio under tip pressure. This opens perspectives for piezotransistor applications.
研究不足
The study is limited to the characterization of the metal-insulator transition under local stress in V2O3 thin films. Further investigations are needed to understand the temperature dependences of conductivity in strained and unstrained films.
1：Experimental Design and Method Selection:
The study used contact atomic force microscopy (C-AFM) to apply local uniaxial stress on a V2O3 thin film. A tip with a large radius was prepared by chemical vapour deposition of platinum onto a commercial tip with a focused ion beam (FIB) to access a sub-gigapascal pressure range.
2：Sample Selection and Data Sources:
A 82 nm thick V2O3 thin film was prepared on a single-crystalline C-plane sapphire substrate using pulsed laser deposition (PLD).
3：List of Experimental Equipment and Materials:
AFM (Omicron), C-AFM, FIB-modified tip, PLD system, XRD (Bruker D8), Quantum Design PPMS for resistivity measurements.
4：Experimental Procedures and Operational Workflow:
The morphology and electric properties of the film were investigated using AFM under an ultrahigh vacuum. Local current-voltage characteristics and temporal evolution of current were carried out under various pressures.
5：Data Analysis Methods:
The conductance and crossover voltage were analyzed to evidence the metal-insulator transition. FEM was used to simulate the strain distribution and c/a ratio under the tip pressure.
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