两端线型双量子点分子Aharonov-Bohm干涉仪电输运

发布时间：2018-06-23 03:24

本文选题：非平衡格林函数 + 量子点　；参考：《物理学报》2015年20期

【摘要】：设计一个两端线型双量子点分子Aharonov-Bohm(A-B)干涉仪.采用非平衡格林函数技术,理论研究无含时外场作用下的体系电导和引入含时外场作用下的体系平均电流.在不考虑含时外场时,调节点间耦合强度或磁通可以诱导电导共振峰劈裂.控制穿过A-B干涉仪磁通的有无,实现了共振峰电导数值在0与1之间的数字转换,为制造量子开关提供了一个新的物理方案.同时借助磁通和Rashba自旋轨道相互作用,获得了自旋过滤.当体系引入含时外场时,平均电流曲线展示了旁带效应.改变含时外场的振幅,实现了体系平均电流的大小与位置的有效控制,而调节含时外场的频率,则可以实现平均电流峰与谷之间的可逆转换.通过调节磁通与Rashba自旋轨道相互作用,与自旋相关的平均电流亦得到有效控制.研究结果为开发利用耦合多量子点链嵌入A-B干涉仪体系电输运性质提供了新的认知.上述结果可望对未来的量子器件设计与量子计算发挥重要的指导作用.
[Abstract]:A linear double quantum dot Aharonov-Bohm (A-B) interferometer is designed. Using the non-equilibrium Green's function technique, the conductance of the system without time-dependent external field and the average current of the system under the action of time-dependent external field are studied theoretically. When the time-dependent external field is not considered, the coupling strength or flux between the regulating points can induce the splitting of the conductance resonance peak. By controlling the flux passing through the A-B interferometer, the digital conversion of the resonant peak conductance between 0 and 1 is realized, which provides a new physical scheme for the fabrication of quantum switches. At the same time, spin filtering is obtained by the interaction of magnetic flux and Rashba spin orbit. When the time-dependent field is introduced into the system, the side-band effect is shown in the average current curve. By changing the amplitude of the time-dependent external field, the magnitude and position of the average current of the system can be effectively controlled, and the reversible conversion between the average current peak and the valley can be realized by adjusting the frequency of the time-dependent external field. By adjusting the interaction between magnetic flux and Rashba spin orbit, the average spin-dependent current can also be effectively controlled. The results provide a new understanding for the development of the electrical transport properties of the coupled multiple quantum dot chains embedded A-B interferometer system. These results are expected to play an important guiding role in the design of quantum devices and quantum computation in the future.
【作者单位】：哈尔滨工程大学理学院纤维集成光学教育部重点实验室;黑龙江工程学院电气与信息工程学院;
【基金】：国家自然科学基金(批准号:11447132) 教育部111引智基地项目(批准号:B13015) 教育部重点实验室计划高等学校基本科研业务费资助的课题~~
【分类号】：O471.1;TH744.3

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