Wang Yaqin, Sui Runqing, Bi Mei, Tang Wu, Ma Sude
Key Laboratory of Fluid and Power Machinery, School of Material Science and Engineering, Xihua University Chengdu 610039 China.
State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China Chengdu 610054 China
RSC Adv. 2019 May 7;9(25):14072-14077. doi: 10.1039/c9ra02146a.
A first-principles electronic structure calculation is utilized to contrastively investigate the crystal structure, band structure, electron effective mass and mobility of perovskite BaSnO under hydrostatic and biaxial strain. Strain-induced changes in relative properties are remarkable and more sensitive to hydrostatic strain than biaxial strain. The structure of BaSnO remains cubic under hydrostatic strain, while it becomes tetragonal under biaxial strain. Originating from the strain sensitivity of the Sn 5s orbitals in the conduction band minimum, the band gaps of BaSnO decrease for both types of strain from -3% to 3%. BaSnO under tensile hydrostatic strain exhibits higher electron mobility than it does under tensile biaxial strain because of the smaller electron effective mass in the corresponding strain. In contrast, the opposite phenomenon exists in compressive strain. Our results demonstrate that strain could be an alternative way to modify the band gap and electron mobility of BaSnO.
利用第一性原理电子结构计算方法，对比研究了钙钛矿型BaSnO在静水压力和双轴应变下的晶体结构、能带结构、电子有效质量和迁移率。应变引起的相关性质变化显著，且静水压力应变比双轴应变更敏感。BaSnO在静水压力应变下保持立方结构，而在双轴应变下变为四方结构。由于导带最小值处Sn 5s轨道对应变敏感，两种应变下BaSnO的带隙从-3%到3%均减小。拉伸静水压力应变下的BaSnO比拉伸双轴应变下具有更高的电子迁移率，因为相应应变下电子有效质量更小。相反，压缩应变下则存在相反现象。我们的结果表明，应变可能是调节BaSnO带隙和电子迁移率的一种替代方法。
