This work presents a theoretical study of the structural and electronic properties of bilayered silicon films under in-plane biaxial strain/stress using density functional theory. Atomic structures of the two-dimensional silicon films are optimized by using both the local-density approximation and generalized gradient approximation. In the absence of strain/stress, five buckled hexagonal honeycomb structures of the bilayered silicon film have been obtained as local energy minima and their structural stability has been verified. These structures present a Dirac-cone shaped energy band diagram with zero energy band gaps. Applying tensile biaxial strain leads to a reduction of the buckling height. Atomically flat structures with zero bucking height have been observed when the AA-stacking structures are under a critical biaxial strain. Increase of the strain between 10.7% ~ 15.4% results in a band-gap opening with a maximum energy band gap opening of ~168.0 meV obtained when 14.3% strain is applied. Energy band diagram, electron transmission efficiency, and the charge transport property are calculated.
Silicon-compatible ideal antiferroelectricity with large digital electromechanical responses enabled by thermal-strain domain engineering
Harbin Institute of Technology, Shenzhen（哈尔滨工业大学（深圳））；Wuhan University of Technology（武汉理工大学）；University of Liège（列日大学）；Tsinghua University（清华大学）；Institute of Metal Research, Chinese Academy of Sciences（中国科学院金属研究所）；Indian Institute of Science（印度科学学院）；Soochow University（苏州大学）；Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）
Two-Dimensional Electron Gas with High Mobility Forming at BaO/SrTiO3 Interface
在两个绝缘氧化物之间的界面处形成的二维电子气（2DEG）为基础研究和器件应用提供了机会。二元碱土金属氧化物具有与硅和钙钛矿氧化物相容的晶格常数，表现出桥接这两种材料类别的多功能性的巨大潜力。在这里，我们报告的2DEG的形成在岩盐BaO和SrTiO 3之间的界面。最高电子迁移率在2 K时达到69000 cm ^2 V.S^-1，导致在高磁场下出现典型的Shubniko de Haas（SdH）振荡。在不同的场角的SdH振荡的存在揭示了准二维字符的费米面。第一性原理计算表明，在界面处从BaO到Ti 3dxy轨道的有效电荷转移是导致所观察到的高载流子迁移率的原因。我们的研究结果表明，BaO/STO异质界面是一个平台，探索相关的量子相，打开了一扇大门，低功耗和介观电子器件。
