Probing interlayer van der Waals strengths of two-dimensional surfaces and defects, through STM tip-induced elastic deformations

A methodology to test the interlayer bonding strength of two-dimensional (2D) surfaces and associated one (1D)- and two (2D)- dimensional surface defects using scanning tunneling microscope tip-induced deformation, is demonstrated. Surface elastic deformation characteristics of soft 2D monatomic sheets of graphene and graphite in contrast to NbSe2 indicates related association with the underlying local bonding configurations. Surface deformation of 2D graphitic moire patterns reveal the inter-layer van der Waals strength varying across its domains. These results help in the understanding of the comparable interlayer bonding strength of 1D grain boundary as well as the grains. Anomalous phenomena related to probing 2D materials at small gap distances as a function of strain is discussed.

Automated summary

A methodology for testing the interlayer bonding strength of 2D surfaces and associated 1D and 2D surface defects using scanning tunneling microscope tip-induced deformation is demonstrated. The surface elastic deformation characteristics of soft 2D monatomic sheets such as graphene and graphite are found to be related to the underlying local bonding configurations. The surface deformation of 2D graphitic moire patterns reveals the varying inter-layer van der Waals strength across its domains. These findings contribute to the understanding of interlayer bonding strength in 1D grain boundaries and grains, as well as anomalous phenomena in probing 2D materials at small gap distances as a function of strain.