Paramagnetic Defects as a Platform for Quantum Spintronics in Diamond

控制固体中单个电子自旋的能力是量子信息处理的宝贵工具。但是还有其他的自由度，比如电子的能级或者单个原子的价态，这些都是很有用的。在物理系量子信息科学（QIS）项目和化学系化学测量与成像（CMI）项目的支持下，Meriles教授将探索如何使用自旋和价态控制的组合来处理信息。最近对钻石中单个色心的光学控制的研究，如氮空位缺陷，已经导致了单电子自旋控制、毫秒级自旋寿命、纠缠和量子逻辑运算的惊人演示。然而，尽管取得了这一进展，由于对其电荷动力学的信息相对较差，对控制这些缺陷的物理的理解是不完整的。为了解决这种知识的缺乏，该项目将探索如何使用电荷态和自旋态-以及它们的相互作用-作为固态量子信息科学的资源。固体中电荷态的相干控制也将促进对影响电荷动力学的基本化学物理因素的理解。该项目解决了有关缺陷电离和重组的重要问题，重点是探索替代电荷相互转换机制（例如，载流子捕获），作为产生所需电荷状态的手段，否则很难通过直接光激发获得。目的是开辟一条将光自旋极化电子注入导带的途径，从而首次通过实验确定块状金刚石中自由载流子的自旋寿命。除了这些基本方面之外，该项目还将为一系列实际应用奠定基础，例如，开发更高效的NV自旋读出协议，以及首次实现用于固体载流子操纵的有源阱。除了量子信息科学之外，这项工作将对点缺陷用作局部探针的广泛应用产生积极影响，例如，通过更有效的自旋读出方案或基于环境对缺陷电荷动力学影响的新传感形式。所获得的知识还可以帮助开发使用电荷状态作为基本信息位的3D高密度光存储器；它也可能为局部改变晶体折射率铺平道路，从而实现光学可重构波导和其他光子结构。除了技术和科学优势外，拟议的研究预计将具有广泛的教育成果，因为它为学生提供了独特的跨学科科学教育，并能够与广泛的合作实验室网络进行互动。这些伙伴关系不仅提供了一个广泛的传播平台，而且还允许PI推进正在进行的外展项目，旨在通过CCNY和东道国大学的暑期活动为贫困学生提供有意义的研究经验。这些计划在城市学院获得了特殊的意义，这是一所少数族裔服务机构，拥有独特的城市学生群体。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The ability to control the spin of individual electrons in solids is a valuable tool for quantum information processing. But there are other degrees of freedom, such as an electron's energy level or the valence state of individual atoms, that would be useful to control as well. With the support from the Quantum Information Science (QIS) program in the Physics Division and the Chemical Measurements and Imaging (CMI) program in the Chemistry Division, Professor Meriles will explore how to use a combination of spin and valence state control to process information. Recent work on optical control of individual color centers in diamond, such as a nitrogen-vacancy defect, has led to stunning demonstrations of single electron spin control, millisecond-long spin lifetimes, entanglement, and quantum logic operations. Despite this progress, however, the understanding of the physics governing such defects is incomplete, due to the comparatively poor information on their charge dynamics. To address this lack of knowledge, this project will explore how to use both charge states and spin states - and their interplay - as a resource for quantum information science in the solid state. Coherent control of charge states in solids will also advance the understanding of fundamental chemical physics factors affecting charge dynamics.The project tackles important questions concerning defect ionization and recombination with emphasis on exploring alternate charge inter-conversion mechanisms (such as, e.g., carrier trapping) as a means to generating desired charge states that are otherwise difficult to attain via direct optical excitation. The aim is to pioneer a path for photo-injecting spin-polarized electrons into the conduction band so as to experimentally determine for the first time the spin lifetime of free carriers in bulk diamond. Adding to these fundamental aspects, the project will lay the groundwork for a range of practical applications including, for example, the development of more efficient NV spin readout protocols and the first implementation of ponderomotive traps for carrier manipulation in the solid state. Beyond quantum information science, this work will positively impact the broad set of applications where point defects are used as local probes, for example, through more efficient spin readout schemes or through new forms of sensing based on the influence of the environment on the defect's charge dynamics. The knowledge to be gained may also help develop 3D high-density optical memories using the charge state as the basic bit of information; it may also pave the route to locally altering the crystal index of refraction so as to implement optically reconfigurable waveguides and other photonic structures. Besides the technological and scientific advantages, the proposed research is expected to have a broad educational outcome because it offers students a unique inter-disciplinary scientific education and the ability to interact with a wide network of collaborating labs. These partnerships not only provide a broad dissemination platform but also allow the PI to advance ongoing outreach programs designed to provide meaningful research experiences to underprivileged students through summer activities within CCNY and at host universities. These plans gain special meaning at City College, a minority serving institution with a uniquely diverse population of inner-city students.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.