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arXiv · 2204.13011

Simplified feedback control system for Scanning Tunneling Microscopy

Francisco Martín-Vega·Víctor Barrena·Raquel Sánchez-Barquilla·Marta Fernández-Lomana·José Benito Llorens·Beilun Wu·Antón Fente·David Perconte Duplain·Ignacio Horcas·Raquel López·Javier Blanco·Juan Antonio Higuera·Samuel Mañas-Valero·Na Hyun Jo·Juan Schmidt·Paul C. Canfield·Gabino Rubio-Bollinger·José Gabriel Rodrigo·Edwin Herrera·Isabel Guillamón·Hermann Suderow
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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 \AA. 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).

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Francisco Martín-Vega, Víctor Barrena, Raquel Sánchez-Barquilla, Marta Fernández-Lomana, José Benito Llorens, Beilun Wu, Antón Fente, David Perconte Duplain, Ignacio Horcas, Raquel López, Javier Blanco, Juan Antonio Higuera, Samuel Mañas-Valero, Na Hyun Jo, Juan Schmidt, Paul C. Canfield, Gabino Rubio-Bollinger, José Gabriel Rodrigo, Edwin Herrera, Isabel Guillamón, Hermann Suderow. 2022-04-27. Simplified feedback control system for Scanning Tunneling Microscopy. https://doi.org/10.1063/5.0064511

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