Method of examining a sample in a scanning tunneling microscope using tip-to-sample distance variations

A method of examining a sample in a microscope equipped with at least one scanning tunneling tip, wherein the sample is placed under the tip, wherein tip coordinates xtip, ytip, ztip are coordinates of the tip in a Cartesian coordinate system with vertical axis (Z) and two horizontal axes X, Y, wherein sample coordinates xsample, ysample, zsample are coordinates in the same Cartesian coordinate system of an arbitrary spot of the sample, wherein tip-to-sample distance D=ztip−zsample is a difference between tip coordinate ztip along the vertical axis Z and sample coordinate zsample along the vertical axis Z, wherein relative tip-to-sample planar coordinates xrel=xtip−xsample and yrel=ytip−ysample are differences between corresponding tip and sample coordinates along horizontal axes X, Y, and wherein between the tip and the sample tunneling current TC can be detected, comprising carrying out the following steps for at least two surface points of the sample:

• placing the tip successively above said surface points of the sample;
• above each of said surface points of the sample, performing a distance varying step comprising varying the tip-to-sample distance D, and
• concurrently with the distance varying step, performing a time dependencies recording step comprising:
• recording time dependency TC(t) of the tunneling current TC, recording time dependencies xrel(t), yrel(t) of the relative tip-to-sample planar coordinates xrel, yrel, and recording time dependency D(t) of the tip-to-sample distance D.