CAREER: Tunable Connate Topological Superconductivity in 2D Transition Metal Dichalcogenides

摘要：超导和量子技术是实现更快、更高效的计算、节能的电力传输和提高材料计量能力的新方法的有希望的途径。实现这种技术的量子态稳健读取的一种方案是将超导性与仅存在于材料边缘的电子态结合起来，从而产生一种融合了这两种性质的特殊状态：天然拓扑超导性。少层过渡金属二硫族化合物是一种很有前途的材料亚类，预测其表现出天然的拓扑超导性，并且在静电环境的适度变化下具有高度可调性。在这个项目中，研究小组的目标是发现、开发和静电控制半金属和超导过渡金属二硫族化合物的天然拓扑超导行为。该项目的成功将引入新的方法来探索超导的新形式，并对控制超导的一般机制有更深入的了解。此外，该项目将研究生和本科生纳入研究工作，并与当地学区的教师合作，为K-12学生开发和开展外展活动。技术摘要：二维共生拓扑超导体是一种独特的系统，其中二维材料的块体内部表现出超导性，而边缘同时具有拓扑非平凡状态。结果，体超导性在非平凡边缘态中诱导超导性，从而产生超导边缘态。本项目的目标是发现、发展和静电控制非中心对称T '和Td二维超导体的共态拓扑超导性和伴随的超导边缘态。对于许多块状材料，已经提出了天然拓扑超导性，但是由于在许多原子层上大量载流子引起的强电子屏蔽，天然拓扑超导性的实验证据和操作仍然有限。具有中等载流子浓度的原子薄T '和Td超导体为更好地理解和控制共生拓扑超导现象提供了机会。由于低电子屏蔽，二维原生拓扑超导体的行为可以在不引入无序的情况下通过静电门控进行调谐。实现一种超越标准Bardeen-Cooper-Schrieffer理论范围的自然拓扑超导体和相关的超导边缘态，将对如何在没有声子促进的情况下出现超导性提供至关重要的见解，并可能对具有长相干时间的工程量子比特有用。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。

Non-Technical Abstract: Superconducting and quantum-based technologies are promising avenues for realizing faster and more efficient computation, energy-efficient transport of electricity, and novel methods that enhance the capabilities of materials metrology. One scheme for realizing robust reading of quantum states for such technologies is to combine superconductivity with electronic states that only exist at the edges of materials, resulting in a special state that merges these two properties: connate topological superconductivity. Few-layer transition metal dichalcogenides are a promising subclass of materials that have been predicted to exhibit connate topological superconductivity and are highly tunable with moderate changes to the electrostatic environment. In this project, the research team aims to discover, develop, and electrostatically control connate topological superconducting behavior in semimetallic and superconducting transition metal dichalcogenides. The success of this project will introduce new methods with which to probe novel forms of superconductivity and lead to greater insight into the general mechanisms that govern superconductivity. In addition, this project integrates graduate and undergraduate students into the research effort and develops and runs outreach activities for K-12 students in collaboration with teachers from local school districts. Technical Abstract: A two-dimensional connate topological superconductor is a unique system where the bulk interior of a two-dimensional material exhibits superconductivity while the edge simultaneously hosts a topologically nontrivial state. As a result, the bulk superconductivity induces superconductivity in the nontrivial edge states, giving rise to superconducting edge states. The goal of this project is to discover, develop, and electrostatically control connate topological superconductivity and the concomitant superconducting edge states in noncentrosymmetric, T’ and Td, two-dimensional superconductors. Connate topological superconductivity has been proposed for a number of bulk materials, but the experimental evidence for and manipulation of connate topological superconductivity has remained limited due to strong electronic screening caused by a large concentration of charge carriers across many atomic layers. Atomically thin T’ and Td superconductors with moderate charge carrier concentrations offer an opportunity to better understand and control connate topological superconductivity phenomena. Because of the low electronic screening, the behavior of two-dimensional connate topological superconductors may be tuned without introducing disorder via electrostatic gating. Realizing a connate topological superconductor and the associated superconducting edge states, which are beyond the scope of standard Bardeen-Cooper-Schrieffer theory, would give crucial insight into how superconductivity can emerge without strictly being facilitated by phonons and could be useful for engineering qubits with long coherence times.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.