Light Modulation of Charge Transfer-Induced Spin-Transfer Processes in Single Molecules for Quantum Information Science

在这个由化学系化学结构、动力学和机制B项目资助的项目中，内华达大学雷诺分校化学系的Natia Frank教授正在开发在光(光致变色)下会变色的化学络合物。这些络合物还表现出随光的磁性变化。在外部刺激(光、电场或磁场)的作用下改变磁性、颜色或电荷的功能材料是计算机、自旋电子学设备和量子信息科学传感器的非易失性存储技术发展的核心。本研究设计开发的材料可作为量子计算、通信、传感器等领域的“量子比特”。一般来说，一个量子比特至少有两个定义明确的状态，可以独立地准备和寻址。量子比特可以与刺激相互作用，产生无限数量的中间态，从而为量子水平的数据处理、存储和传感带来令人兴奋的新可能性。该项目的近期目标是为分子量子比特创建一种通用策略，该策略可以在环境条件下用光控制，从而使嵌入式电阻存储设备和传感器的能源需求显著降低。这项研究位于化学、物理和材料科学的交界处，为学生提供STEM科学的多学科培训。该研究项目还将作为社区参与学习和改进教学做法的平台，以增加不同群体在STEM领域的成功。社区参与的学习活动将包括为初中生和高中生提供有组织的指导活动的研究助学金，以及为本科生课堂上的不同学习者制定新的教学策略。将光学双稳态光致变色配体与电子双稳态金属络合物偶联是一种控制光门功能材料电子结构和寿命的策略。光致变色螺恶嗪配体有两个电子态，可以通过光学选通。当耦合到具有两个基态电子态的双稳钴半醌时，就产生了一个四态电子系统。这种耦合是光异构化诱导的自旋电荷激发态(PISCES)过程，可能导致一种有效的光学选通自旋态的策略。然而，金属中心和光致变色态之间的电子耦合是复杂的，对于阐明电子耦合的主要机制的基础研究是将这一策略扩展到其他基于自旋的体系的核心。该项目将确定在一大类可用作自旋量子比特的电子双稳金属络合物中控制双鱼过程的基本电子和结构因素；评估光学门控金属络合物的自旋动力学和退相干时间，以确定这类基于自旋的量子比特的设计原则；以及确定分子间相互作用对纳米结构薄膜和表面中的双鱼过程、自旋寿命和退相干的影响。该项目的结果可以为基于量子架构的低能量需求传感器和计算应用的加速提供关键的电子耦合参数的基础洞察。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Natia Frank of the Department of Chemistry at the University of Nevada-Reno is developing chemical complexes that change color on exposure to light (photochromic). These complexes also exhibit changes in magnetic properties with light. Functional materials that change magnetism, color or charge upon application of external stimuli (light, electric field, or magnetic field) are central to the development of non-volatile memory technologies for computers, spintronics devices, and sensors for quantum information science. The materials designed and developed in this research can be used as "qubits" in Quantum computing, communications, and sensors. In general, a qubit possesses at least two well-defined states that can be prepared and addressed independently. Qubits can interact with stimuli to generate an infinite number of intermediate states leading to exciting new possibilities for data processing, storage, and sensing at the quantum level. The immediate goal of this project is the creation of a generalized strategy for molecular qubits that can be controlled with light under ambient conditions to enable embedded resistive memory devices and sensors with significantly decreased energy demand. The research lies at the interface of chemistry, physics, and material science, providing multidisciplinary training to students in the STEM sciences. The research project will also serve as a platform for Community Engaged Learning and the development of modified teaching practices for increasing the success of diverse groups in the STEM fields. Community-engaged learning activities will involve research assistantships with structured mentoring activities for middle-school and high-school students and the development of new teaching strategies for diverse learners in the undergraduate classroom. The concept of coupling optically-bistable photochromic ligands to electronically-bistable metal complexes is a strategy for controlling the electronic structure and lifetime of optically-gated functional materials. Photochromic spirooxazine ligands have two electronic states that can be gated optically. When coupled to an electronically bistable cobalt semiquinone with two ground state electronic states, a four-state electronic system is generated. This coupling, a Photoisomerization Induced Spin Charge Excited State (PISCES) process, could lead to a powerful strategy for optically gating spin states. The electronic coupling between metal center and photochrome states, however, is complex, and fundamental studies towards elucidating the primary mechanism of electronic coupling are central to the expansion of this strategy towards other spin-based systems. This project will determine the fundamental electronic and structural factors that govern PISCES processes in a broad class of electronically bistable metal complexes that can serve as spin-qubits; evaluate the spin dynamics and decoherence times for optically-gated metal complexes to determine design principles for this class of spin-based qubits; and determine the effect of intermolecular interactions on PISCES processes, spin lifetimes and decoherence in nanostructured thin films and surfaces. The results of this project could provide fundamental insight into the electronic coupling parameters critical for the acceleration of low-energy demand sensor and computing applications based on quantum architectures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.