Study of properties of the nuclear spin system in bulk n-GaAs by warm-up spectroscopy

In this paper, we present an overview of the possibilities of nuclear spin warm-up spectroscopy method. Nuclear spin warm-up spectroscopy method is based on optical cooling and subsequent warming up of nuclear spins by  oscillating magnetic field. Changes of nuclear spin temperature before and after applying of oscillating magnetic field are determined from the degree of photoluminescence polarization. This method is applied to studying the  properties of the cooled nuclear spin system in bulk n-GaAs crystals. Using warm-up spectroscopy, we can investigate such thermodynamical characteristics of cooled nuclear spins as local fields, absorption coefficients and  fluctuations spectral density (correlator spectrum). In particular, such experimental opportunities accompanied by theoretical interpretations allows us to investigate and control the presence of quadrupole interactions in structures. Furthermore, the nuclear spin fluctuations are reflected in the correlator spectrum, which can be recalculated from absorption coefficients. Measurements of the nuclear spin correlator are important experimental opportunity because fluctuations of nuclear spins are one of the main sources of electron spin decoherence in n-GaAs.