Abstract

We discuss the implications of a small indium content (3%) in a GaAs epilayer on the electron- and nuclear-spin relaxation due to enhanced quadrupolar effects induced by the strain. Using weakly perturbative spin-noise spectroscopy, we study the electron-spin relaxation dynamics without explicit excitation. The observed temperature dependence indicates the presence of localized states, which have an increased interaction with the surrounding nuclear spins. Time-resolved spin-noise spectroscopy is then applied to study the relaxation dynamics of the optically pumped nuclear-spin system. It shows a multi-exponential decay with time components, ranging from several seconds to hundreds of seconds. We also measure the local magnetic field acting between the nuclear spins and identify a strong contribution of quadrupole effects. Finally, we apply a nuclear-spin diffusion model to estimate the concentration of localized carrier states and determine the nuclear-spin diffusion constant characteristic for this system.

Abstract

We discuss the implications of a small indium content (3%) in a GaAs epilayer on the electron- and nuclear-spin relaxation due to enhanced quadrupolar effects induced by the strain. Using weakly perturbative spin-noise spectroscopy, we study the electron-spin relaxation dynamics without explicit excitation. The observed temperature dependence indicates the presence of localized states, which have an increased interaction with the surrounding nuclear spins. Time-resolved spin-noise spectroscopy is then applied to study the relaxation dynamics of the optically pumped nuclear-spin system. It shows a multi-exponential decay with time components, ranging from several seconds to hundreds of seconds. We also measure the local magnetic field acting between the nuclear spins and identify a strong contribution of quadrupole effects. Finally, we apply a nuclear-spin diffusion model to estimate the concentration of localized carrier states and determine the nuclear-spin diffusion constant characteristic for this system.

Abstract

We discuss the implications of a small indium content (3%) in a GaAs epilayer on the electron- and nuclear-spin relaxation due to enhanced quadrupolar effects induced by the strain. Using weakly perturbative spin-noise spectroscopy, we study the electron-spin relaxation dynamics without explicit excitation. The observed temperature dependence indicates the presence of localized states, which have an increased interaction with the surrounding nuclear spins. Time-resolved spin-noise spectroscopy is then applied to study the relaxation dynamics of the optically pumped nuclear-spin system. It shows a multi-exponential decay with time components, ranging from several seconds to hundreds of seconds. We also measure the local magnetic field acting between the nuclear spins and identify a strong contribution of quadrupole effects. Finally, we apply a nuclear-spin diffusion model to estimate the concentration of localized carrier states and determine the nuclear-spin diffusion constant characteristic for this system.

Abstract

We discuss the implications of a small indium content (3%) in a GaAs epilayer on the electron- and nuclear-spin relaxation due to enhanced quadrupolar effects induced by the strain. Using weakly perturbative spin-noise spectroscopy, we study the electron-spin relaxation dynamics without explicit excitation. The observed temperature dependence indicates the presence of localized states, which have an increased interaction with the surrounding nuclear spins. Time-resolved spin-noise spectroscopy is then applied to study the relaxation dynamics of the optically pumped nuclear-spin system. It shows a multi-exponential decay with time components, ranging from several seconds to hundreds of seconds. We also measure the local magnetic field acting between the nuclear spins and identify a strong contribution of quadrupole effects. Finally, we apply a nuclear-spin diffusion model to estimate the concentration of localized carrier states and determine the nuclear-spin diffusion constant characteristic for this system.