Correlation between the electrical conductance and the mechanical deformation of a graphite surface

• A We observe the positive correlation between the contact conductance and the lift length of a graphite.
• We confirm that the top layer of the graphite elastically recovers to the original form.
• Lift length of the single layer graphene on SiO2 substrate is longer than that of the graphite.

We investigate the correlation between the electrical conductance and the mechanical deformation of a graphite surface by using the scanning tunneling microscope break junction (STM-BJ) technique. During STM-BJ, the Au tip is retracted from contact with the graphite surface as the top layer is lifted away from its rest position, resulting in a decrease of the conductance. We observe a positive correlation between the conductance of the contact and the length to which the top layer of graphite is lifted. We also find that the top layer recovers elastically to its original form after detaching from the layer on the tip. Furthermore, the lift length of the top layer of graphite during tip retraction is shorter than that of a single layer of graphene on a silicon oxide surface. Such a characteristic is probably the result of a weaker attractive force of the graphene with Si oxide, such as the van der Waals force, than that of the interlayer interaction of graphite. Our results thus open a new path to basic research of mechano-electronics with carbon-based materials and their applications.