Electronic Energy Levels in an Asymmetric Quantum-Dots-in-a-Well Structure for Infrared Photodetectors

Theoretical calculation of electronic energy levels of an asymmetric InAs/InGaAs/GaAs quantum-dots-in-a-well （DWELL） structure for infrared photodetectors is performed in the framework of effective-mass envelope-function theory. Our calculated results show that the electronic energy levels in quantum dots （QDs） increase when the asymmetry increases and the ground state energy increases faster than the excited state energies. Furthermore, the results also show that the electronic energy levels in Q Ds decrease as the size of QDs and the width of quantum well （QW） in the asymmetric DWELL structure increase. Additionally, the effects of asymmetry, the size of QDs and the width of QW on the response peak of asymmetry DWELL photodetectors are also discussed.     

小班研讨式教学在线演示互动平台的搭建及应用——以多缝衍射的Geogebra模拟演示为例

以光线通过单个及多个狭缝产生的衍射现象这一相关教学知识点的GeoGebra动态演示为案例,介绍了在线演示及互动探索平台的建立方法以及在小班研讨式教学实践中的应用.案例通过一幅图动态展示了各相关物理参量对干涉及衍射结果的影响,不仅能在课堂教学过程中起到很好的辅助作用,而且为学生自主探索隐藏在物理公式后的规律及真相提供了一种易学易用的方法.在线演示及互动探索平台的建立成本低、方法易、效果好,具有很高的应用推广价值.     

Structural Stability and Elastic Properties of Wurtzite TIN under Hydrostatic Pressure

The structural stability and elastic properties of wurtzite thallium nitride （TIN） under hydrostatic pressure are studied for the first time by first-principles calculations. The enthalpy calculations predict that TIN undergoes a phase transition from the wurtzite structure to the rocksalt structure at 19.2 GPa with a volume collapse of 13.0%. Our calculated results also show that this nitride is ductile in nature and exhibits high elastic anisotropy. Our ground-state results are in good agreement with the data of other theoretical calculations.     

Structural, Electronic and Elastic Properties of Cubic Perovskites SrSnO3 and SrZrO3 under Hydrostatic Pressure Effect

Using the plane-wave pesudopotential （PWPP） method within the generalized gradient approximation （GGA＇）, we investigate the hydrostatic pressure induced effect on the structural, electronic and elastic properties of cubic perovskites SrSn03 and SrZr03. The pressure dependence of the lattice constants, some indirect and direct band gaps, the upper valence bandwidths, the elastic stiffness constants and the aggregate elastic moduli, as well as the Debye temperature are investigated. Our calculated ground-state results are in good agreement with the available experimental and theoretical data.     

Pressure-Induced Cubic-to-Hexagonal Phase Transition in Cu2O

Phase transition and band structure of Cu2O are systematically investigated by using the HSE06 range-separated hybrid functional. Cubic Cu2O under pressure transforms to the metastable hexagonal phase. Our further investigations reveal that the first-order phase transition is driven by the elastic and dynamical instabilities. Furthermore, the stable band gap of cubic phase is always direct and greatly enhanced by pressure, whereas the hexagonal phase shows the semi-metallic band structure.     

基于物理学史进行创新性思维培养的教学探索

在充分开发物理学史教学资源的基础上,综合运用思维导图等思维训练工具,构建了“用有趣的科学探索导入课程,用缜密的逻辑思维贯穿课程,用巧妙的研究方法主导课程,用清晰的思维导图巩固课程”的教学模式.在基础物理教学中培养学生的创新性思维,为新工科背景下基础物理教学的改革创新提供了一种思路和方法.     

双单摆串联的稳定运动研究

基于拉格朗日方程和稳定运动状态的条件,我们给出了稳定运动时串联双单摆系统参数需要满足的条件。与实验结果比较发现,该条件与实验结果非常吻合。     

用方位径向摆演示李萨如图形的研究

通过对方位径向摆的弹性杆和摆球的固有振动频率进行分析,利用相机曝光方法研究了摆球李萨如图形.分析了摆线长度、初始释放角度、摆球质量等因素对摆球运行轨迹的影响,理论和实验符合较好.     

二维光子晶体中赝磁场作用下的电磁波操控

在经典波系统中,赝磁场作为人工合成的规范场,可以像真实磁场一样调控波的传输,从而受到了人们的广泛关注.本文利用在二维光子晶体中引入单向线性梯度形变的方式,构建空间均匀分布的赝磁场.强赝磁场的存在导致光子晶体出现朗道能级量子化.与真实磁场不同,光子晶体赝磁场在两个不等价的能谷中相反,系统的时间反演对称性没有被打破.设计的光子晶体支持边界态的输运,并且能够使波束的传输路径发生弯曲.将具有相反赝磁场的光子晶体构造在一起还能够实现有趣的“蛇态”传输,为操控电磁波的传输并设计信息处理器件提供了良好的平台.