Establishment of photocarrier injection method by which electronic properties of strongly correlated materials can be controlled.

研究了过渡金属氧化物薄膜的光载流子注入及其电子态。我们观察到了软X射线辐照引起的VO2薄膜从绝缘体到金属的转变。在软X射线照射下，电子载流子被注入到V3D带中。我们提出了一个简单的模型，其中转变是由薄膜中氧的脱附驱动的。用角分辨光电子能谱(ARPES)研究了金属VO2薄膜的费米表面拓扑结构，发现存在嵌套矢量。近顶层的CrO2薄膜由表面敏感的光电子能谱揭示为金属。此外，还制备了单相TaO_2薄膜和调幅分解(V，Ti)O_2薄膜。

Photocarrier injection to transition metal oxide thin films and the electronic states of the films are investigated. We have observed an insulator-to-metal transition of VO2 thin films induced by soft X-ray irradiation. Electron carriers are injected into the V 3d band upon soft-X ray irradiation. We propose a simple model where the transition is driven by desorption of oxygen from the films. The Fermi surface topology of a metallic VO2 thin film is studied by angle-resolved photoemission spectroscopy (ARPES) and the nesting vector is found to be present. Near topmost layer of CrO2 thin films are revealed to be metallic by surface sensitive PES. Also, a single-phase TaO2 thin film and spinodally decomposed (V,Ti)O2 thin film are developed.