Exploring tunable magnet/superconductor hybrid quantum systems via scanning tunneling microscopy

通过扫描隧道显微镜探索可调磁体/超导体混合量子系统

• 批准号: 459025680
• 负责人: Dr. Roberto Lo Conte, Ph.D.
• 金额: --
• 依托单位: Institut für Nanostruktur- und Festkörperphysik (INF)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2021
• 资助国家: 德国
• 起止时间: 2020-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/459025680?language=en
• 关键词: Exploring; tunable; magnet; superconductor; hybrid

In recent years the investigation of quantum materials has been experiencing an unprecedented acceleration, mostly due to the promise of applications in the upcoming quantum information technologies. Magnet/superconductor hybrid (MSH) systems are very promising candidates for designing new quantum materials with tunable properties. Rich new physics is expected to emerge at the interface between a superconducting substrate and an ultrathin magnetic layer hosting non-collinear spin-textures. On the one hand, the superconducting state of the substrate is expected to influence the magnetic phase established in the ultrathin magnet. On the other hand, topologically protected electronic states are predicted to be present at the hetero-interface due to the interplay between the non-collinear spin-texture and the superconducting phase, allowing for the emergence of topological superconductivity.This project focuses on the investigation of new MSH quantum systems via spin-polarized scanning tunnelling microscopy (SP-STM). The atomic spin texture in the deposited magnetic layers will be imaged as a function of temperature and magnetic fields, allowing to understand the influence of superconductivity on the magnetic phase established in the ultra-thin film. In addition, scanning tunnelling spectroscopy (STS) will be used to investigate the electronic properties of the hybrid system and to unveil the emergence of topological superconductivity. The electronic properties will be characterized at the location of physical (edges of nanostructures) as well as magnetic (domain walls) boundaries, in the attempt to distinguish among the different possible origins of topological electronic states. This kind of investigation will be done on two different types of MSH systems. The initial study will be conducted on materials systems consisting of a bulk superconductor with on top magnetic monolayers and double-layers. Subsequently, the study will move towards slightly more complex systems, where a very thin interlayer of a second superconducting material will be inserted at the interface of the initial magnet/superconductor system. The aim is to understand how the properties of the initial MSH system can be tuned by the presence of a second superconducting material via proximity effects. What will be the superconducting transition temperature of the whole system? Can the transition temperature and so the quantum properties of the trilayer be tuned by changing the thickness of the superconducting interlayer? How does the spin-texture change as a function of the material and the thickness of the interlayer? Can different topological superconducting states be stabilized by changing the interlayer? These are some of the key scientific questions that this research project will try to answer.

近年来，对量子材料的调查一直在经历前所未有的加速度，这主要是由于在即将到来的量子信息技术中应用的承诺。磁铁/超导体混合动力车（MSH）系统是设计具有可调特性的新量子材料的非常有前途的候选者。预计有丰富的新物理学将在超导底物与托有非共线自旋纹理的超薄磁层之间的界面上浮出水面。一方面，底物的超导状态有望影响超薄磁体中建立的磁相。另一方面，由于非连续性旋转文本和超导阶段之间的相互作用，拓扑保护的电子状态被预测存在于异距离间接，从而允许拓扑超导性的出现。该项目侧重于研究新的MSH Quantum Systems通过Spinum Quantum Systems通过Spinum-polar-polarized Scanning tunneling Microsspopy（Sp-Sp-Stm）进行研究。沉积磁层中的原子自旋纹理将作为温度和磁场的函数成像，从而了解超导性对超薄膜中建立的磁相的影响。此外，扫描隧道光谱法（STS）将用于研究混合系统的电子特性，并揭示拓扑超导性的出现。电子特性将在物理（纳米结构的边缘）以及磁性（域壁）边界的位置进行表征，以区分拓扑电子状态的不同可能起源。这种调查将对两种不同类型的MSH系统进行。最初的研究将对由大量超导体组成的材料系统进行，并在顶部磁性单层和双层层上进行。随后，该研究将朝着稍微复杂的系统移动，其中将在初始磁铁/超导体系统的界面上插入第二个超导材料的非常薄的层中。目的是了解如何通过接近效应的第二个超导材料来调整初始MSH系统的性能。整个系统的超导过渡温度将是多少？是否可以通过更改超导层间层的厚度来调整三层的过渡温度和量子性能？自旋文本如何随着材料的函数和层的厚度而变化？可以通过更改层间稳定不同的拓扑超导状态吗？这些是该研究项目将尝试回答的一些关键科学问题。