Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Sci Adv. 2019 Nov 8;5(11):eaaw5593. doi: 10.1126/sciadv.aaw5593. eCollection 2019 Nov.
Graphene is a powerful playground for studying a plethora of quantum phenomena. One of the remarkable properties of graphene arises when it is strained in particular geometries and the electrons behave as if they were under the influence of a magnetic field. Previously, these strain-induced pseudomagnetic fields have been explored on the nano- and micrometer-scale using scanning probe and transport measurements. Heteroepitaxial strain, in contrast, is a wafer-scale engineering method. Here, we show that pseudomagnetic fields can be generated in graphene through wafer-scale epitaxial growth. Shallow triangular nanoprisms in the SiC substrate generate strain-induced uniform fields of 41 T, enabling the observation of strain-induced Landau levels at room temperature, as detected by angle-resolved photoemission spectroscopy, and confirmed by model calculations and scanning tunneling microscopy measurements. Our work demonstrates the feasibility of exploiting strain-induced quantum phases in two-dimensional Dirac materials on a wafer-scale platform, opening the field to new applications.
石墨烯是研究多种量子现象的强大平台。当石墨烯在特定几何形状下受到拉伸时,其电子的行为就像是受到磁场的影响,这是石墨烯的一个显著特性。以前,这些应变诱导的赝磁场已经在纳米级和微米级使用扫描探针和输运测量进行了研究。相比之下,异质外延应变是一种晶圆级的工程方法。在这里,我们通过晶圆级外延生长展示了在石墨烯中产生赝磁场的方法。SiC 衬底中的浅三角纳米棱柱产生了应变诱导的均匀磁场 41 T,使得在室温下观察到了应变诱导的朗道能级,这一结果通过角分辨光发射谱得到了证实,并通过模型计算和扫描隧道显微镜测量得到了确认。我们的工作证明了在晶圆级平台上利用二维狄拉克材料中的应变诱导量子相的可行性,为新的应用开辟了道路。