2017/12/07 by Si-Yu Li, Siyu Li, Haiwen Liu +3 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Biasing #Condensed matter physics #Conductance #Dirac fermion #Graphene #Graphene research and applications #Landau quantization #Magnetic field #Materials science #Molecular Junctions and Nanostructures #Nanotechnology #Optoelectronics #Physics #Quantum and electron transport phenomena #Quantum mechanics #Quantum tunnelling #Resonator #Scanning tunneling microscope #Scanning tunneling spectroscopy #Voltage #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.97.115442
published as Phys. Rev. B 97, 115442 (2018) · 4 figures in main text
arxiv created 2017/12/07 · openalex created_date 2017/12/22 · openalex publication_date 2018/03/26 · arxiv updated 2018/04/04 · openalex updated_date 2026/08/05
Negative differential conductance (NDC), characterized by the decreasing current with increasing voltage, has attracted continuous attention for its various novel applications. The NDC typically exists in a certain range of bias voltages for a selected system and controlling the regions of NDC in curves of current versus voltage (I\text\ensuremath-V) is experimentally challenging. Here, we demonstrate a magnetic-field-controlled NDC in scanning tunneling spectroscopy of graphene npn junction resonators. The magnetic field not only can switch on and off the NDC, but also can continuously tune the regions of the NDC in the I\text\ensuremath-V curves. In the graphene npn junction resonators, magnetic fields generate sharp and pronounced Landau-level peaks with the help of the Klein tunneling of massless Dirac fermions. A tip of scanning tunneling microscope induces a relatively shift of the Landau levels in graphene beneath the tip. Tunneling between the misaligned Landau levels results in the magnetic-field-controlled NDC.