External field control of a few-particle-bound states in double quantum dots

双量子点中少数粒子束缚态的外场控制

• 批准号: 16540282
• 负责人: NATORI Akiko
• 金额: $ 1.41万
• 依托单位: The University of Electro-Communications
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540282/
• 关键词: double quantum dots; spin coupling; electron correlation; quantum Monte Carlo method; Hubbard model; spin correlation; magnetic field

We study both spin and charge correlations between two electrons in vertically coupled quantum dots with a finite well width using a diffusion quantum Monte Carlo method, and clarify mechanism of their dependences on both a barrier thickness and a magnetic field on the basis of analysis in the Hubbard model.When the barrier thickness increases, two-electron occupation probability in the same dot is suppressed drastically by enhanced charge correlation relative to electron transfer effect and the magnitude of the anti-ferromagnetic spin coupling decreases in two stages.By applying magnetic field, both the anti-ferromagnetic spin coupling and the two-electron occupation probability in the same dot are suppressed, being caused by enhanced intra-dot charge correlation.In the case of weak lateral confinement in dots, serial switching of the ground states can also be induced by increasing magnetic field and alternation of spin coupling between anti-ferromagnetic coupling and ferromagnetic coupling occurs.

利用扩散量子Monte Carlo方法研究了有限阱宽垂直耦合量子点中两个电子之间的自旋和电荷关联，并在Hubbard模型分析的基础上阐明了它们对势垒厚度和磁场的依赖机制.当势垒厚度增加时，相对于电子转移效应的电荷关联增强和反电子的大小，铁磁自旋耦合分两个阶段减弱，外加磁场抑制了反铁磁自旋耦合和同一点的双电子占据几率，这是由于点内电荷关联增强所致，在点内横向约束较弱的情况下，通过增加磁场也可以引起基态的连续切换，并且发生反铁磁耦合和铁磁耦合之间的自旋耦合的交替。

项目成果

Electronic and magnetic properties of BNC ribbons

• DOI: 10.1103/physrevb.72.205429
• 发表时间: 2005-11-01
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Nakamura, J;Nitta, T;Natori, A
• 通讯作者: Natori, A

Charge correlation and spin coupling in double quantum dots : a quantum diffusion Monte Carlo study

双量子点中的电荷相关性和自旋耦合：量子扩散蒙特卡罗研究

• 发表时间: 2006
• 期刊: Phys.Rev.B (to be submitted)
• 作者: H. Madokoro;T. Shimizu;and Y. Motizuki;H.Masu
• 通讯作者: H.Masu