Giant orbital magnetic moments and paramagnetic shift in artificial relativistic atoms and molecules
Giant orbital magnetic moments and paramagnetic shift in artificial relativistic atoms and molecules
复制标题
DOI：
10.1038/s41565-023-01327-0
复制
发表时间：
2022-10
影响因子：
38.3
通讯作者：
Zhehao Ge;S. Slizovskiy;Peter Polizogopoulos;T. Joshi;T. Taniguchi;Kenji Watanabe;D. Lederman;V. Fal’ko;J. Velasco
中科院分区：
文献类型：
--
作者：
Zhehao Ge;S. Slizovskiy;Peter Polizogopoulos;T. Joshi;T. Taniguchi;Kenji Watanabe;D. Lederman;V. Fal’ko;J. Velasco
石墨烯和拓扑绝缘体等材料含有无质量狄拉克费米子，可以研究相对论量子现象。由无质量狄拉克费米子形成的单量子点和耦合量子点可以分别被视为人工相对论原子和分子。这种结构为研究超相对论范围（粒子速度接近光速）下的原子和分子物理提供了一个独特的测试平台。在这里，我们使用扫描隧道显微镜来创建和探测单个和耦合的静电定义的石墨烯量子点，以揭示人工相对论纳米结构的磁场响应。我们在单个石墨烯量子点中观察到巨大的轨道塞曼分裂和高达〜70 meV T–1和〜600μB（μB，玻尔磁子）的轨道磁矩。对于耦合石墨烯量子点，观察到阿哈罗诺夫-玻姆振荡和~20 meV T-2 的强 Van Vleck 顺磁位移。我们的研究结果提供了对相对论量子点态的基本见解，可以潜在地用于量子信息科学。
Materials such as graphene and topological insulators host massless Dirac fermions that enable the study of relativistic quantum phenomena. Single quantum dots and coupled quantum dots formed with massless Dirac fermions can be viewed as artificial relativistic atoms and molecules, respectively. Such structures offer a unique testbed to study atomic and molecular physics in the ultrarelativistic regime (particle speed close to the speed of light). Here we use a scanning tunnelling microscope to create and probe single and coupled electrostatically defined graphene quantum dots to unravel the magnetic-field responses of artificial relativistic nanostructures. We observe a giant orbital Zeeman splitting and orbital magnetic moment up to ~70 meV T–1and ~600μB(μB, Bohr magneton) in single graphene quantum dots. For coupled graphene quantum dots, Aharonov–Bohm oscillations and a strong Van Vleck paramagnetic shift of ~20 meV T–2are observed. Our findings provide fundamental insights into relativistic quantum dot states, which can be potentially leveraged for use in quantum information science.