Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Four-point probe measurements using current probes with voltage feedback
  to measure electric potentials   We present a four-point probe resistance measurement technique which uses
four equivalent current measuring units, resulting in minimal hardware
requirements and corresponding sources of noise. Local sample potentials are
measured by a software feedback loop which adjusts the corresponding tip
voltage such that no current flows to the sample. The resulting tip voltage is
then equivalent to the sample potential at the tip position. We implement this
measurement method into a multi-tip scanning tunneling microscope setup such
that potentials can also be measured in tunneling contact, allowing in
principle truly non-invasive four-probe measurements. The resulting measurement
capabilities are demonstrated for BiSbTe$_3$ and Si$(111)-(7\times7)$ samples.

22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol