CNIC: U.S.-Swedish Engineering Research on Spin Blockaded Transport and Onset of Wigner Crystallization in All Electric Spin Valves

CNIC：美国-瑞典关于所有电动自旋阀中自旋封锁输运和维格纳结晶开始的工程研究

• 批准号: 1341789
• 负责人: Marc Cahay
• 金额: $ 5.33万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341789&HistoricalAwards=false
• 关键词: CNIC; U.S.; Swedish; Engineering; Research

To realize the full potential of spin-based devices, ways must be found to inject, manipulate, and detect the spin of the electron by purely electrical means. Recently, the Principal Investigator (PI) successfully demonstrated that lateral spin orbit coupling (LSOC) can be used to create a strongly spin-polarized current by purely electrical means; that is, in the absence of any applied magnetic field. The PI proposes to extend these studies to spin valve structures composed of a quantum dot or wire coupled to the source and drain via asymmetrically biased quantum point contacts (QPCs). With an asymmetric bias on the gates of the two QPCs, their spin filtering, when combined with Coulomb blockaded transport through the active channel, should lead to spin-blockaded transport through the spin valve. When operated close to threshold, all electrical spin valves could also be used to investigate new many-body effects, such as electrically controlled spontaneous spin polarization, Wigner crystallization and formation of spin lattices in nanoscale devices, which are burgeoning fields of spintronics research.Intellectual Merit:The proposed planning visit to initiate research with Swedish partners at the University of Linkoping to provide the first theoretical investigation of the Coulomb/Spin Blockades and Wigner Crystallization regimes of operation in all-electric spin valves in the presence of LSOC. Since these many-body effects cannot be modeled using a one-particle Hamiltonian approach, the cooperative technical approach will be to develop a theoretical framework based on a multi-particle Fock space and steady-state rate equations, and to calculate the conductance of these spin valves. Theoretical efforts will complement recent experimental efforts at the University of Cincinnati to create all electric spin valves and other recent reports on quantum manipulation of single spins in quantum dots which rely on subtle spin correlation effects leading to intriguing non-linear transport phenomena such as Negative Differential Region (NDR), multiple NDR, and bistability.Broader Impacts:A thorough understanding of the Coulomb and Spin Blockades, and Wigner crystallization in all electric spin valves in the presence of LSOC would be a major milestone in the field of spintronics. A deep understanding of these non-linear effects in strongly correlated systems will contribute to future advancement in fields where non-equilibrium dynamics are involved. If successful, this project is likely to theoretically produce the first simulator that includes the effects of Coulomb and Spin blockade and models spin transport in nanoscale devices in the presence of LSOC. The software developed will be useful to investigate heterostructure parameters for design and fabrication of all electric spin valves for applications in spin-based sensors, spin filters, multilevel logic circuits and data storage applications. The project described is intended to catalyze new collaboration between the School of Electronics and Computing Systems at the University of Cincinnati and the Department of Physics, Chemistry and Biology in Linkoping, Sweden. This effort will serve as a precursor for long-term collaboration between Cincinnati and Linkoping Universities to engage undergraduate and graduate physics/engineering students in both countries through a research exchange program during which the students would benefit from the guidance of engineers and physicists with complementary expertise.

为了实现基于自旋的设备的全部潜力，必须找到方法以通过纯电气方式注入，操纵和检测电子的自旋。 最近，主要研究者（PI）成功证明了侧向自旋轨道耦合（LSOC）可用于通过纯电气手段创建强旋转电流。也就是说，在没有任何应用磁场的情况下。 PI建议将这些研究扩展到由量子点或电线组成的旋转阀结构，并通过不对称的质量点接触（QPC）通过不对称的偏置量子点（QPC）排水。 在两个QPC的大门上有不对称的偏置，当与库仑通过活跃通道的封闭传输结合时，它们的自旋滤波应导致通过自旋阀进行自旋阻滞转运。 当操作接近阈值时，所有电旋转阀也可以用于研究新的多体效应，例如电气控制的自发性自旋极化，wigner结晶和纳米级设备中自旋晶格的形成，它们正在迅速发展，它们正在迅速启动，这些领域正在启动旋转的研究：Intellectualics研究：提议的计划来访问瑞士的链接，以促进瑞士的链接，以促进瑞典的链接，该链接构成了瑞典的链接，该链接是瑞典的一部分，该链接构成了一会儿的一部分。在LSOC存在下，库仑/自旋封锁和WIGNER结晶机构在全电动旋转阀中的运行状态。 由于这些多体效应无法使用单粒子的哈密顿方法进行建模，因此合作技术方法将是基于多粒子Fock空间和稳态速率方程的理论框架，并计算这些自旋阀的电导。 理论努力将补充辛辛那提大学的最新实验努力，以创建所有电动旋转阀以及有关量子点中单次旋转的量子操纵的其他最新报告，这些量子依赖于微妙的旋转相关效应，从而导致非线性运输现象，例如吸引人的不线差异区域（例如负差异区域（NDR），多个NDR和BIDERAIDE。在LSOC存在下的电旋转阀将是Spintronics领域的主要里程碑。 对这些非线性效应在密切相关的系统中的深刻理解将有助于在涉及非平衡动态的领域的未来进步。 如果成功的话，该项目很可能在理论上产生了第一个模拟器，其中包括库仑和自旋封锁的效果以及在LSOC存在下纳米级设备中自旋传输的效果。 开发的软件将有助于研究用于设计和制造所有电动旋转阀的异质结构参数，用于在基于旋转的传感器，旋转过滤器，多级逻辑电路和数据存储应用程序中应用。所描述的项目旨在促进辛辛那提大学电子与计算系统学院与瑞典Linkoping的物理，化学和生物学系之间的新合作。 这项工作将成为辛辛那提与链接大学之间长期合作的先驱，以通过研究交流计划在两国与本科生和研究生物理/工程专业的学生互动，在此期间，学生将受益于工程师和物理学家的补充专业知识的指导。