Magnetically confined graphene quantum dots

磁约束石墨烯量子点

• 批准号: 400112579
• 负责人: Professor Dr. Markus Morgenstern
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/400112579?language=en
• 关键词: Magnetically; confined; graphene; quantum; dots

This project is based on our recent realization of smoothly confined graphene quantum dots using Landau level gaps in combination with local electric fields. These dots appear to be much more controlled in terms of filling sequences by orbital, valley and spin levels than lithographic graphene quantum dots, which typically suffer from edge disorder. In particular, robust orbital and valley splittings are identified, in excellent agreement with detailed tight-binding calculations. Changing the lateral position of the quantum dot by sub-nm displacements with respect to the superstructure of graphene on hexagonal boron nitride additionally allows for accurate tuning of the different energy scales with variations in the 10 meV range. These remarkable results are so far restricted to the tip of a scanning tunneling microscope, which is used simultaneously to charge and to probe the quantum dot. This project aims to- develop multiple contact experiments including back gates and additional side contacts in order to provide tuning and precise control of this novel type of quantum dot,- perform dynamic measurements of the quantum dot electrons down to the sub-ns time scale targeting the exploitation of the theoretically predicted favorable relaxation and coherence properties of graphene quantum dots.- develop a comprehensive theoretical model to understand the dot dynamics at different time and length scales.

这个项目是基于我们最近利用朗道能级能隙结合局部电场实现了光滑限制的石墨烯量子点。与平版石墨烯量子点相比，这些点在填充顺序方面似乎更受轨道、山谷和自旋能级的控制，后者通常受到边缘无序的影响。特别是，确定了稳健的轨道分裂和山谷分裂，这与详细的紧束缚计算非常一致。通过改变量子点相对于六方氮化硼上石墨烯超结构的亚纳米位移来改变量子点的横向位置，还可以在10 meV范围内精确调节不同的能量尺度。到目前为止，这些显著的结果仅限于扫描隧道显微镜的尖端，扫描隧道显微镜同时用于充电和探测量子点。该项目的目标是-开发包括后门和附加侧接触的多接触实验，以提供对这种新型量子点的调谐和精确控制，-针对石墨烯量子点的理论预测的良好驰豫和相干特性，对量子点电子进行精确的动态测量。-开发一个全面的理论模型，以了解不同时间和长度尺度上的量子点动力学。