2019/01/08 by H. Graef, Quentin Wilmart, Q. Wilmart +21
Materials Science · Physics and Astronomy · #Condensed matter physics #Dirac (video compression format) #Dirac fermion #Dirac sea #Fermion #Graphene #Graphene research and applications #Helical Dirac fermion #Phonon #Physics #Quantum and electron transport phenomena #Quantum mechanics #Scattering #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1038/s41467-019-10326-6
11 pages, 4 figures
arxiv created 2019/01/08 · openalex publication_date 2019/06/03 · arxiv updated 2019/06/19 · openalex created_date 2019/08/13 · openalex updated_date 2026/08/05
Dirac fermion optics exploits the refraction of chiral fermions across optics-inspired Klein-tunneling barriers defined by high-transparency p-n junctions. We consider the corner reflector (CR) geometry introduced in optics or radars. We fabricate Dirac fermion CRs using bottom-gate-defined barriers in hBN-encapsulated graphene. By suppressing transmission upon multiple internal reflections, CRs are sensitive to minute phonon scattering rates. Here we report on doping-independent CR transmission in quantitative agreement with a simple scattering model including thermal phonon scattering. As a signature of CRs, we observe Fabry-Pérot oscillations at low temperature, consistent with single-path reflections. Finally, we demonstrate high-frequency operation which promotes CRs as fast phonon detectors. Our work establishes the relevance of Dirac fermion optics in graphene and opens a route for its implementation in topological Dirac matter.