Nickel–nitrogen complexes in synthetic diamond: the 1.660 eV luminescence system

Abstract

In this paper, we report the effects of applied uniaxial stress and temperature dependence of the 1.660eV zero phonon line (ZPL) observed in high-pressure high-temperature synthetic diamonds, grown using an Ni solvent catalyst and annealed at 1600°C. It is shown that stress dependence of the 1.660eV line can be understood in terms of an electric dipole transition between A and B states at a centre of monoclinic I symmetry, with the electric dipole lying in the plane normal to the main symmetry axis at an angle of ∼75° to the 〈1−10〉 crystal axis.The shape of the vibronic sideband is explained using a simple electron–lattice coupling model. The temperature effects on the ZPL are discussed in the framework of linear and quadratic electron–phonon coupling.