Cr in diamond: A first-principles study

Abstract

We report ab initio pseudopotential DFT calculations on the energetic stability and magnetic ordering of Cr in diamond at various lattice sites and charge states and show that Cr is most stable at the divacancy site in diamond, with the lowest formation energy occurring in $n$- or $p$-type diamond, compared to intrinsic diamond. The incorporation of Cr introduces strongly spin polarized impurity bands into the diamond band gap, with both the spin polarization and magnetic stabilization energies critically dependent on the charge state of Cr and the position of the Fermi level in diamond. In $p$-type diamond, we predict Cr${}^{+2}$ at the divacancy site possesses a ferromagnetic stabilization energy of 17 meV and magnetic moment of 2.5 ${\ensuremath{\mu}}_{\mathrm{B}}$, with Cr in diamond likely to form a diluted ferromagnetic semiconductor, which may successfully be considered for room temperature spintronic applications.