  We explore the adsorption of MoS2 on a range of metal substrates by means of
first-principles density functional theory calculations. Including van der
Waals forces in the density functional is essential to capture the interaction
between MoS2 and a metal surface, and obtain reliable interface potential steps
and Schottky barriers. Special care is taken to construct interface structures
that have a mismatch between the MoS2 and the metal lattices of <1%. MoS2 is
chemisorbed on the early transition metal Ti, which leads to a strong
perturbation of its (electronic) structure and a pinning of the Fermi level
0.54 eV below the MoS2 conduction band due to interface states. MoS2 is
physisorbed on Au, where the bonding hardly perturbs the electronic structure.
The bonding of MoS2 on other metals lies between these two extreme cases, with
interface interactions for the late 3d transition metals Co, Ni, Cu and the
simple metal Mg that are somewhat stronger than for the late 4d/5d transition
metals Pd, Ag, Pt and the simple metal Al. Even a weak interaction, such as in
the case of Al, gives interface states, however, with energies inside the MoS2
band gap, which pin the Fermi level below the conduction band.
