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G. Feldbauer, M. Wolloch, P. Bedolla Velazquez, P. Mohn, J. Redinger, A. Vernes:
"Adhesion and material transfer between contacting Al and TiN surfaces from first principles";
Physical Review B, 91 (2015), 1654131 - 16541313.

A series of density functional theory (DFT) simulations was performed to investigate the approach, contact,
and subsequent separation of two atomically flat surfaces consisting of different materials. Aluminum (Al)
and titanium nitride (TiN) slabs were chosen as a model system representing a metal-ceramic interface and
the interaction between soft and hard materials. The approach and separation were simulated by moving one
slab in discrete steps normal to the surfaces allowing for electronic and atomic relaxations after each step.
Various configurations were analyzed by considering (001), (011), and (111) surfaces as well as several lateral
arrangements of these surfaces at the interface. Several tests were conducted on the computational setup, for
example, by changing the system size or using different approximations for the exchange correlation functional.
The performed simulations revealed the influences of these aspects on adhesion, equilibrium distance, and
material transfer. These interfacial properties depend sensitively on the chosen configuration due to distinct bond
situations. Material transfer, in particular, was observed if the absolute value of the adhesion energy for a given
configuration is larger than the energy cost to remove surface layers. This result was found to be independent
of the employed exchange correlation functional. Furthermore, it was shown that a simple comparison of the
surface energies of the slabs is not sufficient to predict the occurrence of material transfer.