Wu Meng, Huang Si Zhao, Zeng Hui, Koster Gertjan, Huang Yu Yang, Zheng Jin Cheng, Wang Hui Qiong
Fujian Provincial Key Laboratory of Semiconductors and Applications, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen 361005, People's Republic of China.
1 MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
J Synchrotron Radiat. 2019 Sep 1;26(Pt 5):1687-1693. doi: 10.1107/S1600577519007094. Epub 2019 Jul 12.
The correlation between electronic properties and epitaxial strain in a cation-deficient system has rarely been investigated. Cation-deficient SrVO films are taken as a model system to investigate the strain-dependent electrical and electronic properties. Using element- and charge-sensitive soft X-ray absorption, V L-edge absorption measurements have been performed for SrVO films of different thicknesses capped with 4 u.c. (unit cell) SrTiO layers, showing the coexistence of V and V in thick films. A different correlation between V valence state and epitaxial strain is observed for SrVO ultrathin films, i.e. a variation in V valence state is only observed for tensile-strained films. SrVO thin films are metallic and exhibit a thickness-driven metal-insulator transition at different critical thicknesses for tensile and compressive strains. The asymmetric response of electrical conductivity to strain observed in cation-deficient SrVO films will be beneficial for functional oxide electronic devices.
在阳离子缺陷体系中，电子性质与外延应变之间的相关性鲜有研究。以阳离子缺陷的SrVO薄膜作为模型体系，来研究应变依赖的电学和电子性质。利用元素和电荷敏感的软X射线吸收，对覆盖有4个晶胞（单位晶胞）SrTiO层的不同厚度的SrVO薄膜进行了V L边吸收测量，结果表明厚膜中存在V和V的共存。对于SrVO超薄膜，观察到V价态与外延应变之间存在不同的相关性，即仅在拉伸应变薄膜中观察到V价态的变化。SrVO薄膜是金属性的，并且在拉伸和压缩应变的不同临界厚度下表现出厚度驱动的金属-绝缘体转变。在阳离子缺陷的SrVO薄膜中观察到的电导率对应变的不对称响应将有利于功能性氧化物电子器件。
