Quantum Strain Control: Exploring Quantum Materials under Applied Uniaxial Strain

这项提议的目标是研究如何通过施加机械应变来调节并最终控制新型量子材料的电子和磁性。有许多量子材料家族具有在量子设备和技术中具有开创性应用的潜力。这包括高温超导体(无损电力传输、超高磁场)、量子自旋液体(容错量子计算机)和磁性天离子材料(超快磁存储器)。然而，物理学家研究的材料(大块单晶)和用于实际器件的材料(外延薄膜)之间往往存在着根本的脱节。最明显的差异是应变的存在：薄膜通常生长在衬底材料上，薄膜和衬底之间的任何不匹配都会导致机械应变。类似的应变可以通过单轴应变室以一种更可调的方式应用于散装材料。应变可以是控制材料物理性质的一种极其强大的工具。它可以用来扩展或压缩材料的结构，改变原子间的距离和键角，从而决定电子带宽和磁相互作用的性质。应变还可以用来破坏对称性，为发现新的量子相提供了一条途径。应变可以作为“机械去孪晶”的实验工具，使材料中的结构或磁区对齐，使研究本征性质变得更容易。也许最有趣的是，应变可以用来弥合大块单晶和外延薄膜之间的差距，允许在大块材料中设计和复制特定的应变条件。我们建议与美国康奈尔大学的研究人员建立一个新的合作关系，研究量子材料的电子和磁性在外加机械应变下的演化。这一合作将使我们能够：(1)获得用于X射线散射和光谱分析的最先进的单轴应变室；(2)在麦克马斯特开发令人兴奋的新实验能力；(3)为康奈尔高能同步加速器源的麦克马斯特HQP提供独特的培训体验。

The goal of this proposal is to investigate how the electronic and magnetic properties of novel quantum materials can be tuned, and ultimately controlled, by applied mechanical strain. There are many families of quantum materials with potential for ground-breaking applications in quantum devices and technology. This includes high temperature superconductors (lossless power transmission, ultrahigh magnetic fields), quantum spin liquids (fault-tolerant quantum computers), and magnetic skyrmion materials (ultrafast magnetic memory). However, there is often a fundamental disconnect between the materials studied by physicists (bulk single crystals) and those used in practical devices (epitaxial thin films). The most obvious discrepancy is the presence of strain: thin films are typically grown on substrate material, and any mismatch between film and substrate introduces mechanical strain. Similar strains can be applied in bulk materials, in a more tunable fashion, with a uniaxial strain cell. Strain can be an extremely powerful tool for controlling the physical properties of materials. It can be used to expand or compress the structure of a material, varying interatomic distances and bond angles that determine the nature of electronic bandwidths and magnetic interactions. Strain can also be used to break symmetries, providing a route to discover new quantum phases. Strain can be used as an experimental tool for "mechanical detwinning", aligning the structural or magnetic domains in a material and making it easier to investigate intrinsic properties. Perhaps most intriguingly, strain can be used to bridge the gap between bulk single crystals and epitaxial thin films, allowing specific strain conditions to be designed and reproduced in bulk materials. We propose to establish a new collaboration with researchers at Cornell University (USA) to study how the electronic and magnetic properties of quantum materials evolve under applied mechanical strain. This collaboration will allow us to: (1) acquire a state-of-the-art uniaxial strain cell for x-ray scattering and spectroscopy, (2) develop exciting new experimental capabilities at McMaster, and (3) provide a unique training experience for McMaster HQP at the Cornell High Energy Synchrotron Source.