First-principles calculations on the electronic structure of Co-doped diamond

Abstract

Doping behavior of Cobalt (Co) in diamond was investigated by using density functional theory (DFT). Formation energies, work functions, and charge distributions were calculated for Co atoms substituted at different depths in the (111) and (220) planes. The results show that Co incorporation is energetically favorable in the shallow layers of both surfaces, but becomes progressively less stable at greater depths. On both crystal planes, Co doping reduces the work function by approximately 0.25 eV, suggesting enhanced electron emission and higher surface reactivity. Charge density analysis further reveals significant electron transfer between Co and neighboring carbon atoms, forming mixed covalent-ionic bonds and inducing local lattice distortions. These electronic and structural modifications highlight the potential of Co-doped diamond as a tunable material for catalytic and electronic applications. The findings provide theoretical guidance for future experimental studies aimed at exploiting transition-metal doping to tailor diamond's functional properties.