Warm-up spectroscopy of quadrupole-split nuclear spins in n-GaAs epitaxial layers

The efficiency of the adiabatic demagnetization of the nuclear spin system (NSS) of a solid is limited, if quadrupole effects are present. Nevertheless, despite a considerable quadrupole interaction, recent experiments validated the thermodynamic description of the NSS in GaAs. This suggests that nuclear spin temperature can be used as a probe of nuclear magnetic resonances. We implement this idea by analyzing the modification of the NSS temperature in response to an oscillating magnetic field at various frequencies, an approach termed as the warm-up spectroscopy. It is tested in a n-GaAs sample where both mechanical strain and built-in electric field may contribute to the quadrupole splitting, yielding the parameters of electric field gradient tensors for As-75 and both Ga isotopes, Ga-69 and Ga-71.

Automated summary

The efficiency of adiabatic demagnetization of the nuclear spin system in a solid is limited by quadrupole effects. However, recent experiments in GaAs validate the thermodynamic description of the NSS despite a significant quadrupole interaction. This suggests that nuclear spin temperature can be used as a probe of nuclear magnetic resonances.