A Zero-loop Sagnac Interferometer for Probing Spontaneous Time Reversal Symmetry Breaking in Topological Superconductors

用于探测拓扑超导体自发时间反演对称性破缺的零环萨格纳克干涉仪

• 批准号: RTI-2021-00322
• 负责人: Ye, Ziliang
• 金额: $ 2.84万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718832
• 关键词: Zero; loop; Sagnac; Interferometer; Probing

This proposal is for the purchase of equipment required to build a zero-loop Sagnac interferometer for probing Kerr rotation with a sub-µrad sensitivity and a µm spatial resolution. The biggest breakthrough in two-dimensional materials recently is inarguably the discovery of correlated phases and superconductivity in twisted bilayer graphene. In addition, the successful isolation of monolayer high-temperature (Tc) superconductors was just reported last year. Inspired by these developments, our theorist colleague, Marcel Franz, proposed a new theory predicting that the first high-Tc topological superconductor can emerge out of a twisted bilayer of d-wave superconductors. The theory predicts that when two monolayers of d-wave superconductors are stacked with a forty-five degree twist angle, a /2 phase difference arises in the superconducting order parameter between the two layers. As a result, the total superconducting order parameter acquires chiral symmetry and the high-Tc superconductor becomes a high-Tc topological superconductor with a topological gap. Here we propose to experimentally test this theory by fabricating twisted bilayers of a high-Tc superconductor, Bi2Sr2CaCu2O8+, and probing their topological superconducting phase with light. According to the theory, the time reversal symmetry will spontaneously break below the transition temperature, which will give rise to a Polar Kerr Effect. Since the topological gap is much smaller than the probe light's photon energy, the Kerr rotation angle is expected to fall below µrad. Therefore we plan to build a state-of-the-art Sagnac interferometer with an extreme sensitivity for Kerr rotation (tens of nrads). This instrument will allow us to demonstrate the first high-Tc topological superconductor, as well as resolve some open fundamental questions in the field. Our new approach to realizing topological superconductivity at high temperature might enable new opportunities for topological quantum computing in the future. In collaboration with colleagues, we will also apply the proposed equipment to probing the marginal time reversal symmetry breaking in other low-dimensional systems, such as the twisted bilayer graphene (Folk group), the MBE-grown monolayer ferromagnet, Fe3GeTe2 (Zou group), the surface state in HfNiSn along the (111) direction (Aronson group), high-entropy magnetic alloys (Hallas group), and transition-metal dichalcogenide heterostructures, which is of my own group's interest. The experience of working with the state-of-the-art Sagnac interferometer will provide our HQPs with extremely valuable skills which will help their careers both within and beyond academia.

该建议是用于购买建造零环的SAGNAC干涉仪所需的设备，以探测Kerr旋转，并具有亚拉德敏感性和µM空间分辨率。最近，二维材料中最大的突破是不可能发现相关相和扭曲双层石墨烯中的超导性。此外，去年刚刚据报道，成功隔离单层高温（TC）超导体。受这些发展的启发，我们的理论同事马塞尔·弗朗兹（Marcel Franz）提出了一种新理论，预测第一个高-TC拓扑超导体可以从D扭曲的D-WAVE超导体的双层中出现。该理论预测，当两个D-Wave超导体的两个单层堆叠在45度角角时，两个层之间的超导体顺序参数会出现A /2相差。结果，总超导体顺序参数获得了手性对称性，而高-TC超导体成为具有拓扑间隙的高-TC拓扑超导体。 在这里，我们建议通过制造高-TC超导体，BI2SR2CACU2O8+的扭曲的双层，并用光探测其拓扑超导阶段，从而实验测试该理论。根据该理论，时间逆向对称性将在过渡温度以下中断，这将产生极地KERR效应。由于拓扑间隙远小于探针光的光子能量，因此Kerr旋转角有望降至µrad以下。因此，我们计划建立一个最先进的SAGNAC干涉仪，对Kerr旋转极为敏感（数十NRADS）。该工具将使我们能够展示第一个高-TC拓扑超导体，并解决该领域的一些开放基本问题。我们在高温下实现拓扑超导性的新方法可能会在将来实现拓扑量子计算的新机会。 通过与同事合作，我们还将应用提出的设备来探测其他低维系统中的边缘时间逆转对称性破裂，例如扭曲的双层石墨烯（民间群体），MBE成长的单层单层Ferromagnet，Fe3gete2（Zou group），fe3gete2（Zou group），沿HFNISNISNISNISNETER沿HFNISN的表面状态（111）（111）方向（ARONY）（ARONY）； （Hallas Group）和过渡金属二甲藻元化异源结构，这是我自己的兴趣。与最先进的SAGNAC干涉仪合作的经验将为我们的HQP提供极为宝贵的技能，这将有助于他们在学术界内外的职业。