2020/09/24 by A. Iordanescu, S. Toussaint, G. Bachelier +5
Engineering · Physics and Astronomy · #Characterization (materials science) #Conical surface #Electron #Electron holography #Electrostatics #Interferometry #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena #RADIUS #Scanning electron microscope #Scanning gate microscopy #Semiconductor #Surface and Thin Film Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1063/5.0023698
published as Appl. Phys. Lett. 117, 193101 (2020)
arxiv created 2020/09/24 · openalex created_date 2020/10/01 · openalex publication_date 2020/11/09 · arxiv updated 2020/11/13 · openalex updated_date 2026/08/05
Using the tip of a scanning probe microscope as a local electrostatic gate gives access to real-space information on electrostatics as well as charge transport at the nanoscale, provided that the tip-induced electrostatic potential is well known. Here, we focus on the accurate characterization of the tip potential, in a regime where the tip locally depletes a two-dimensional electron gas (2DEG) hosted in a semiconductor heterostructure. Scanning the tip in the vicinity of a quantum point contact defined in the 2DEG, we observe Fabry–Pérot interference fringes at low temperature in maps of the device conductance. We exploit the evolution of these fringes with the tip voltage to measure the change in the depletion radius by electron interferometry. We find that a semi-classical finite-element self-consistent model taking into account the conical shape of the tip reaches a faithful correspondence with the experimental data.