Angle-resolved optically detected magnetic resonance as a tool for strain determination in nanostructures

Abstract

In this paper, we apply the angle-resolved Optically Detected Magnetic Resonance (ODMR) technique to study series of strained (Cd, Mn)Te/(Cd, Mg)Te quantum wells (QWs) produced by molecular beam epitaxy. By analyzing characteristic features of ODMR angular scans, we determine strain-induced axial-symmetry spin Hamiltonian parameter D with neV precision. Furthermore, we use low-temperature optical reflectivity measurements and X-ray diffraction scans to evaluate the local strain present in QW material. In our analysis, we take into account different thermal expansion coefficients of GaAs substrate and CdTe buffer. The additional deformation due to the thermal expansion effects has the same magnitude as deformation origination from the different compositions of the samples. Based on the evaluated deformations and values of strain-induced axialsymmetry spin Hamiltonian parameter D, we find strain spin-lattice coefficient G11 = (72.2 ± 1.9) neV for Mn 2+ in CdTe and shear deformation potential b = (−0.94 ± 0.11) eV for CdTe.