量子点间隧穿对库仑拖拽效应的影响  

Effect of tunneling between quantum dots on Coulomb drag effect

作　　者：武嘉羽 邹永连 WU Jiayu;ZOU Yonglian(School of Physics and Optoelectronics,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]湘潭大学物理与光电工程学院,湖南湘潭411105

出　　处：《湘潭大学学报（自然科学版）》2023年第3期34-44,共11页Journal of Xiangtan University(Natural Science Edition)

基　　金：国家自然科学基金(2020111200101)。

摘　　要：当材料尺寸限制在纳米级时,电子在输运的过程中会产生明显的量子效应.库仑拖拽效应是由一个处于偏压的系统和一个无偏压系统的库仑相互作用所产生的一种量子输运现象.纳米结构中的电子流动会因为库仑相互作用变得相关,这种相关程度由电荷能控制.该效应背后的机制同时依赖于拖拽系统的不对称耦合.该文用主方程的方法计算了双量子以并联的方式耦合产生的拖拽效应.除了库仑相互作用和有限的外部电位偏差,还考虑到了双量子点间的弱耦合导致的单电子局域隧穿过程.当量子点之间处于弱耦合并且在允许隧穿的情况下,所产生的拖拽效应并不依赖于拖拽系统的不对称耦合.量子点间隧穿通道的建立对拖拽电流产生了很大的贡献,通过调谐门电压控制量子点能级的位置,产生新的单电子输运图像丰富了拖拽效应的理论研究.In electron transport,significant quantum effects can occur if the material size is limited to the nanometer scale.The Coulomb drag effect is a quantum transport phenomenon caused by the Coulomb interaction between a biased system and an unbiased system.The electron flow in the nanostructure becomes correlated due to Coulomb interactions,and the degree of correlation is controlled by the charge energy.The mechanism behind this effect also relies on the asymmetric coupling of the drag system.In this paper,the drag effect of double quanta coupled in parallel is calculated by using master equation method.In addition to the coulomb interaction and the limited external potential deviation,the single-electron local tunneling process caused by the weak coupling between the double QDs(Quantum Dots)is also considered.When the dots are weakly coupled and tunneling is allowed,the drag effect does not depend on the asymmetric coupling of the drag system.The position of quantum dot energy level is controlled by tuning gate voltage.The establishment of the tunneling channel between quantum dots makes a great contribution to the drag current,and the new single-electron transport image generated enriches the theoretical study of the drag effect.

关 键 词：库仑相互作用 量子输运 库仑拖拽效应 不对称耦合 

分 类 号：O631[理学—高分子化学]