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

TL;DR

This study demonstrates that angle-resolved ODMR can precisely measure strain in quantum wells by analyzing spin Hamiltonian parameters, complemented by optical and X-ray techniques to evaluate local strain effects.

Contribution

The paper introduces a method combining angle-resolved ODMR with optical and X-ray measurements for accurate strain determination in nanostructures.

Findings

Determined strain-induced axial-symmetry spin Hamiltonian parameter D with neV precision.

Evaluated local strain in quantum wells using optical reflectivity and X-ray diffraction.

Calculated strain spin-lattice coefficient G11 and shear deformation potential b for Mn2+ in CdTe.

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 axial-symmetry spin Hamiltonian parameter D, we find strain spin-lattice coefficient G11 = (72.2 +- 1.9) neV for Mn2+ in CdTe and shear deformation potential b = (-0.94 +- 0.11) eV for CdTe.