Performance analysis and implementation of a scanning tunneling potentiometry setup: Toward low-noise and high-sensitivity measurements of the electrochemical potential


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Date

2021-10

Publication Type

Journal Article

ETH Bibliography

yes

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Data

Abstract

Scanning tunneling potentiometry allows for studying charge transport on the nanoscale to relate the local electrochemical potential to morphological features of thin films or two-dimensional materials. To resolve the influence of atomic-scale defects on the charge transport, sub-µV sensitivity for the electrochemical potential is required. Here, we present a complete analysis of the noise in scanning tunneling potentiometry for different modes of operation. We discuss the role of various noise sources in the measurements and technical issues for both dc and ac detection schemes. The influence of the feedback controller in the determination of the local electrochemical potential is taken into account. Furthermore, we present a software-based implementation of the potentiometry technique in both dc and ac modes in a commercial scanning tunneling microscopy setup with only the addition of a voltage-controlled current source. We directly compare the ac and dc modes on a model resistor circuit and on epitaxial graphene and draw conclusions on the advantages and disadvantages of each mode. The effects of sample heating and the occurrence of thermal voltages are discussed.

Publication status

published

Editor

Book title

Volume

92 (10)

Pages / Article No.

103707

Publisher

American Institute of Physics

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Organisational unit

03986 - Gambardella, Pietro / Gambardella, Pietro check_circle

Notes

Funding

163225 - Local detection of spin accumulation by scanning probe microscopy (SNF)

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