Spin transport properties in double quantum rings connected in series

A new model of metal/semiconductor/metal double-quantum-ring connected in series is proposed and the transport properties in this model are theoretically studied.The results imply that the transmission coefficient shows periodic variations with increasing semiconductor ring size.The effects of the magnetic field and Rashba spin-orbit interaction on the transmission coefficient for two kinds of spin state electrons are different.The number of the transmission coefficient peaks is related to the length ratio between the upper arm and the half circumference of the ring.In addition,the transmission coefficient shows oscillation behavior with enhanced external magnetic field,and the corresponding average value is related to the two leads’ relative position.     

IGBT高压大功率驱动和保护电路的应用研究

通过对功率器件IGBT的工作特性分析、驱动要求和保护方法等讨论，介绍了的一种可驱动高压大功率IGBT的集成驱动模块HCPL-316J的应用。     

用晶格玻尔兹曼方法进行气液相变虚拟实验

用晶格玻尔兹曼方法真实地再现了过饱和气体成核凝结成液滴的过程.通过用品格玻尔兹曼方法接近真实地模拟气液相变虚拟实验,创造性地将复杂系统模拟方法用于大学物理虚拟实验,可以有效地给学生创设了建构知识的学习环境.     

三终端多臂量子环中的持续电流

本文提出了三终端多臂量子环模型,并采用特殊方法来计算持续电流,研究发现：总磁通为零时,持续电流随半导体环增大做非周期和不等幅的振荡.总磁通不为零时,持续电流随AB磁通增强做周期性等幅振荡,Rashba自旋轨道耦合具有改变两种持续电流位相和位相差的效应. 平均持续电流的大小与各臂的臂长和所处的位置以及磁通分布相关.AB磁通对两种持续电流具有不同影响,两种持续电流是可分离的.     

Persistent spin currents in a triple-terminal quantum ring with three arms

A new model of a triple-terminal quantum ring with three arms is proposed.We develop an equivalent method for reducing the triple-terminal quantum ring to the double-terminal quantum ring and calculate the persistent spin currents in this model.The results indicate that the persistent spin currents show behavior of nonperiodic and unequal amplitude oscillation with increasing semiconductor ring size when the total magnetic flux is zero. However,when the total magnetic flux is non-zero,the persistent spin currents make periodic equal amplitude oscillations with increasing AB magnetic flux intensity.At the same time,the two kinds of spin state persistent spin currents have the same frequency and amplitude but the inverse phase.In addition,the Rashba spin-orbit interaction affects the phase and the phase difference of the persistent spin currents.The average persistent spin currents relate to the arm length and the terminal position as well as the distribution of the magnetic flux in each arm.Furthermore, our results indicate that the AB magnetic flux has different influences on the two kinds of spin state electrons.     

串联量子环自旋输运的性质

摘要：本文提出了金属/半导体/金属结构的串联量子环模型,研究表明：透射概率随半导体环增大发生振荡,AB磁通和Rashba自旋轨道耦合对两种自旋态电子的透射概率具有不同影响,A臂臂长和πR的比值与透射概率主共振峰的个数相关。透射概率随外加磁场增强发生振荡,其平均值随 角的减小而增大。