A combined atomic force- and tunneling microscopy system at 10mK temperature

ORAL

Abstract

We present the implementation of atomic force microscopy (AFM) with a self-sensing quartz tuning fork (qPlus) sensor in our ultra-low temperature scanning tunneling microscopy (STM) system. The system operates in an ultra-high vacuum (UHV) environment inside a dilution refrigerator (DR) with a base temperature of 10mK and magnetic fields up to 15T[1]. Radio frequency (RF) filtering of all signal lines entering the UHV chamber and improved home built RF powder filters at low temperatures were implemented to produce an improved energy resolution in tunneling spectroscopy, i.e. a lower effective electron temperature. Low noise preamplifiers for the sensor deflection[2] and the STM current signal[3] were implemented at the 4K stage within the DR. This allows for reduced Johnson noise of the amplifier feedback resistors and a relatively short distance (1.2m) between amplifier and the mK stage and magnet where the sensor is operating. As cable capacity between sensor and amplifier adds noise, a special cable with a capacity of merely 30pF/m has been designed and implemented.

[1] Song et al., RSI 81, 121101 (2010); doi: 10.1063/1.3520482
[2] Huber and Giessibl, RSI 88, 073702 (2017); doi: 10.1063/1.4993737
[3] adapted from le Sueur and Joyez, RSI 77, 123701 (2006); doi: 10.1063/1.2400024

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Presenters

  • Johannes Schwenk

    Center for Nanoscale Science and Technology, National Institue of Standards and Technology, Center for Nanoscale Science and Technology, NIST

Authors

  • Johannes Schwenk

    Center for Nanoscale Science and Technology, National Institue of Standards and Technology, Center for Nanoscale Science and Technology, NIST

  • Sungmin Kim

    Center for Nanoscale Science and Technology, National Institue of Standards and Technology, Center for Nanoscale Science and Technology, NIST

  • Julian Berwanger

    Institut für Experimentelle und Angewandte Physik, Universität Regensburg

  • Steven Blankenship

    Center for Nanoscale Science and Technology, National Institue of Standards and Technology, Center for Nanoscale Science and Technology, NIST

  • William Cullen

    Center for Nanoscale Science and Technology, National Institue of Standards and Technology, Center for Nanoscale Science and Technology, NIST

  • Young Kuk

    Dept. of Physics and Astronomy, Seoul National University, Department of Physics and Astronomy, Seoul National University

  • Franz Giessibl

    Institut für Experimentelle und Angewandte Physik, Universität Regensburg

  • Joseph Stroscio

    Center for Nanoscale Science and Technology, NIST, Center for Nanoscale Science and Technology, NIST -Natl Inst of Stds & Tech, NIST -Natl Inst of Stds & Tech, Center for Nanoscale Science and Technology, National Institue of Standards and Technology, Center for Nanoscale Science and Technology, National Institute of Standards and Technology, NIST