Defect Configurations and Ionization Energies of Carbon Vacancies, Hydrogen, Boron and Their Complexes in Diamond

We present first principles density functional theory calculations of boron, hydrogen, interstitial carbon atoms and their complexes in diamond. Such complexes are expected to form in boron-implanted diamond samples, where the hydrogen is present as a remnant of the diamond growth process. The ground state configurations of these defects are evaluated and the corresponding ionization energies are estimated using the marker method. We present comparisons with literature wherever available. Earlier work in this area has primarily explored the ground state configurations and defect energies by considering the system as a spin-degenerate state. Here, both the spin-degenerate as well as the spin-polarized calculations are performed to identify the minimum energy configuration and explore local magnetic moments on atomic sites. A few saddle point structures are also discovered in the relaxation process at intermediate energies and correspond to previously unreported defect configurations. In the future, these ground state configurations of the defect complexes can provide the relevant energies for investigating the diffusion of defects in diamond.