Simplified feedback control system for Scanning Tunneling Microscopy

Abstract

A Scanning Tunneling Microscope (STM) is one of the most important scanning probe tools available to study and manipulate matter at the nanoscale. In a STM, a tip is scanned on top of a surface with a separation of a few Å. Often, the tunneling current between tip and sample is maintained constant by modifying the distance between the tip apex and the surface through a feedback mechanism acting on a piezoelectric transducer. This produces very detailed images of the electronic properties of the surface. The feedback mechanism is nearly always made using a digital processing circuit separate from the user computer. Here we discuss another approach, using a computer and data acquisition through the USB port. We find that it allows succesful ultra low noise studies of surfaces at cryogenic temperatures. We show results on different compounds, a type II Weyl semimetal (WTe${}_2$), a quasi two-dimensional dichalcogenide superconductor (2H-NbSe${}_2$), a magnetic Weyl semimetal (Co${}_3$Sn${}_2$S${}_2$) and an iron pnictide superconductor (FeSe).

arXiv commentInstrumentation paper

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Cited by in corpus (10)

• Quantum-well states at the surface of the heavy-fermion superconductor URu${}_2$Si${}_2$
• Band structure, superconductivity and polytypism in AuSn${}_4$
• Superconducting density of states and bandstructure at the surface of the candidate topological superconductor Au2Pb
• Superconducting density of states of PtPb4
• Superconducting density of states and vortex lattice of LaRu${}_2$P${}_2$ observed by Scanning Tunneling Spectroscopy
• Electronic band structure from quasiparticle interference and Landau quantization in WTe${}_2$
• The feedback driven atomic scale Josephson microscope
• Advanced approach of superconducting gap function extraction from tunneling experiments
• Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
• Scanning Tunneling Microscopy in high vectorial magnetic fields