Cross-calibration of GaAs deformation potentials and gradient-elastic tensors using photoluminescence and nuclear magnetic resonance spectroscopy in GaAs/AlGaAs quantum dot structures

TL;DR

This study combines photoluminescence and nuclear magnetic resonance spectroscopy to accurately determine deformation potentials and gradient-elastic tensors in GaAs/AlGaAs quantum dot structures under uniaxial stress, improving understanding of strain effects.

Contribution

It provides new experimental measurements of the ratio of deformation potentials and the product of nuclear quadrupolar moments with gradient-elastic tensor components in GaAs, with signs of tensor components directly measurable.

Findings

Determined the ratio b/a=0.241±0.008 in GaAs.

Derived QS11 values for 75As and 69Ga nuclei, with signs measurable.

Found QS11 values 1.4 times smaller than previous nuclear acoustic resonance results.

Abstract

Lattice matched GaAs/AlGaAs epitaxial structures with quantum dots are studied under static uniaxial stress applied either along the $[001]$ or $[110]$ crystal directions. We conduct simultaneous measurements of the spectral shifts in the photoluminescence of the bulk GaAs substrate, which relate to strain via deformation potentials $a$ and $b$, and the quadrupolar shifts in the optically detected nuclear magnetic resonance spectra of the quantum dots, which relate to the same strain via the gradient-elastic tensor $S_{ijkl}$. Measurements in two uniaxial stress configurations are used to derive the ratio $b/a=0.241\pm0.008$ in good agreement with previous studies on GaAs. Based on the previously estimated value of $a\approx-8.8$ eV we derive the product of the nuclear quadrupolar moment $Q$ and the $S$-tensor diagonal component in GaAs to be $QS_{11}\approx+0.76\times10^{-6}$ V for $^{75}$As and $QS_{11}\approx-0.37\times10^{-6}$ V for $^{69}$Ga nuclei. In our experiments the signs of $S_{11}$ are directly measurable, which was not possible in the earlier nuclear acoustic resonance studies. Our $QS_{11}$ values are a factor of $\sim$1.4 smaller than those derived from the nuclear acoustic resonance experiments [Phys. Rev. B 10, 4244 (1974)]. The gradient-elastic tensor values measured in this work can be applied in structural analysis of strained III-V semiconductor nanostructures via accurate modelling of their magnetic resonance spectra.