Is there any substrate that is better than Ir(1 0 0) for diamond nucleation?

The initial nucleation of adsorbed carbon (-C) and hydrocarbon groups (-CH,-C2H2,-CH2 and  -CH3) on Ir, Pt, Au, Rh, and Co(1 0 0) surfaces are investigated for diamond heteroepitaxial. It is revealed that the carbon-hydrogen ratios of the adsorbed species play a key role: The relative stabilities of these species vary while the coverage increases; at full coverage, only  -C2H2 is favorable on the surface. The Ir(1 0 0) surface is unique: it binds with the  -C2H2 the most strongly. The study not only answers why Ir(1 0 0) is by far the best substrate for diamond heteroepitaxy, but also points out the searching direction for even better substrate materials.