Spin-photon interfaces based on isoelectronic centers in semiconductors

量子网络使用光子来传输量子态并在处理节点之间分配纠缠;它们实现了分布式计算和安全通信。它们是由转换静止量子位和光子量子位的物理接口构建的。固态自旋量子位提供了最清晰的可扩展性路径，被积极开发为自旋光子接口。我的团队成功地开创了使用等电子中心（IC）作为自旋光子接口的先河，IC是一种光学可寻址的半导体缺陷。在上一个资助周期中，我们为他们的理解做出了重大贡献，并展示了其他系统无法结合的两个战略优势：NV中心的高光学均匀性和外延量子点的大偶极矩。此外，我们还揭示了轻空穴和重空穴的存在，并展示了新的和强大的光学控制方案。这些成就表明我们有能力独立开发该领域的新研究方向。鉴于集成电路提供的引人注目的机会，该资助周期致力于进一步推进对这种自旋量子比特系统的研究。更具体地说，我建议阐明自旋弛豫和退相干机制，并利用其独特的特性，以解决两个突出的问题，阻碍发展的基于半导体的自旋光子接口：自旋相干时间在直接带隙半导体短。为了解决这个问题，我们利用1）在II-VI族材料中O和Te IC提供的稀核自旋环境和2）在几个核上的束缚自旋的极端局部化。这两个方面可以产生一个局部的“核自旋自由”的环境，其中没有核自旋位于电子或空穴波函数之下，从而抑制这种占主导地位的退相干机制。半导体纳米结构面临的这个重要问题通过在单个磁场配置中利用轻空穴和重空穴状态来解决：轻空穴trions为初始化和控制提供了lambda结构，重空穴trions为读出提供了循环跃迁。通过开发原创方法并解决两个基本限制，我们的研究计划致力于量子信息的最高科学影响，这是一个有希望革新信息技术的重要研究领域。在短期内，该计划使学生能够在经典和量子光学，固态物理和设备以及精密仪器方面发展出色的实验技能。这些技能在信息和通信行业非常受欢迎，该行业在过去十年中一直是加拿大经济增长最快的部门。

Quantum networks use photons to transport quantum states and distribute entanglement between processing nodes; they enable distributed computation and secure communications. They are built from physical interfaces converting stationary and photon qubits. Providing the clearest paths to scalability, solid-state spin qubits are actively developed as spin-photon interfaces.My group has successfully pioneered the use of isoelectronic centers (ICs), an optically-addressable semiconductor defect, as spin-photon interfaces. In the last grant cycle, we have made significant contributions to their understanding and demonstrated two strategic advantages that no other system combines: the high optical homogeneity of NV centers and the large dipole moments of epitaxial quantum dots. In addition, we have revealed the existence of light-and heavy-hole trions and demonstrated new and powerful optical control schemes. These accomplishments demonstrate our capacity to independently develop new research directions in this field. In the light of the compelling opportunities offered by ICs, this grant cycle is dedicated to further advancing the research on this spin qubit system. More specifically, I propose to elucidate spin relaxation and decoherence mechanisms and exploit their distinctive characteristics to address two outstanding issues impeding the development of semiconductor-based spin-photon interfaces:Spin coherence times in direct gap semiconductors are short. To address this issue, we take advantage of 1) the dilute nuclear spin environment offered by O and Te ICs in II-VI materials and 2) the extreme localization of the bound spin over a few nuclei. These two aspects can yield a local “nuclear-spin-free” environment where no nuclear spin is located underneath the electron or hole wavefunction, thereby suppressing this dominant decoherence mechanism.Actual schemes for optical initialization, control, and single-shot read-out are mutually incompatible. This important issue facing semiconductor nanostructures is solved by exploiting both light- and heavy-hole states in a single magnetic field configuration: light-hole trions provide the lambda structure for initialization and control and heavy-hole trions provide the cycling transition for read-out.By developing an original approach and by addressing two fundamental limitations, our research program strives for the highest scientific impact in quantum information, a prominent research field that promises to revolutionize information technologies. In the short term, this program enables students to develop outstanding experimental skills in classical and quantum optics, solid-state physics and devices, and precision instrumentation. These skills are highly sought in information and communication industry, which has been the fastest growing sector of the Canadian economy over the last ten years.