Manipulation of nuclear spin dynamics in n-GaAs using an on-chip microcoil

Abstract

We present an approach for electrically manipulating nuclear spins in n-GaAs using an on-chip microcoil. Optically injected spin-polarized electrons are used to generate a dynamic nuclear polarization via electron-nucleus hyperfine interaction with a characteristic time constant of ∼10 min. The saturated Overhauser field amplitude is on the order of several 10 mT and proportional to the spin polarization degree of the injected electrons. Applying an rf field resonant for the A75s nuclei, complete depolarization of A75s nuclear spins is observed.

Nuclear magnetization in gallium arsenide quantum dots at zero magnetic field

“…Electrical control of the nuclear spins allows to access complementary information910. These effects, predicted originally for metals11, manifest themselves by giant hyperfine fields of nuclear origin experienced by localized electrons12 and can influence their spin polarization in the same way as an external magnetic field.…”

“…The investigation of dynamic nuclear polarization (DNP) effects in bulk semiconductors 1 2 , in quantum wells 3 4 and in quantum dots (QDs) 5 6 under circularly polarized light excitation has been a very active field of research for more than 30 years, both from a fundamental point of view and for potential applications in quantum computing and NMR imaging 7 8 . Electrical control of the nuclear spins allows to access complementary information 9 10 . These effects, predicted originally for metals 11 , manifest themselves by giant hyperfine fields of nuclear origin experienced by localized electrons 12 and can influence their spin polarization in the same way as an external magnetic field.…”