2015/02/03 by Wei Yan, Si-Yu Li, Siyu Li +5
Chemistry · Materials Science · Mathematics · Physics and Astronomy · #Bilayer #Bilayer graphene #Chemistry #Condensed matter physics #Dirac fermion #Electron #Graphene #Graphene research and applications #Landau quantization #Materials science #Mathematics #Membrane #Monolayer #Nanotechnology #Physics #Planar #Quantization (signal processing) #Quantum Hall effect #Quantum and electron transport phenomena #Quantum mechanics #Quantum tunnelling #Scanning tunneling microscope #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.93.195408
3 Figures in main text
arxiv created 2015/02/03 · openalex publication_date 2016/05/06 · arxiv updated 2016/05/25 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Hybrid quantum Hall (QH) junctions have been extensively studied by transport measurements due to their exciting physics and device applications. Here we report on spatially resolving electronic properties of such a junction on the nanoscale. We present a subnanometer-resolved scanning tunneling microscopy (STM) and scanning tunneling spectroscopy study of a monolayer-bilayer graphene planar junction in the QH regime. The atomically well-defined interface of such a junction allows us to spatially resolve the interface electronic properties. Around the interface, we detect Landau quantization of massless Dirac fermions as expected in the graphene monolayer for filled states of the junction, whereas unexpectedly, only Landau quantization of massive Dirac fermions as expected in the graphene bilayer is observed for empty states. The observed unconventional interface Landau quantization arises from the fact that the quantum conductance across the interface is solely determined by the minimum filling factors (number of edge modes) in the graphene monolayer and bilayer regions of the junction. Our finding opens the way to spatially explore the QH effect of different graphene hybrid structures only using a STM.