arXiv subjects

M. Hanson

Publications and source records attributed to M. Hanson.

20 records · Page 2Linked to original sources

arXiv2003

Spin and Polarized Current from Coulomb Blockaded Quantum Dots

We report measurements of spin transitions for GaAs quantum dots in the Coulomb blockade regime, and compare ground and excited state transport spectroscopy to direct measurements of the spin polarization of emitted current. Transport spectroscopy reveals both spin-increasing and spin-decreasing transitions as well as higher-spin ground states, and allows g-factors to be measured down to a single electron. The spin of emitted current in the Coulomb blockade regime, measured using spin-sensitive electron focusing, is found to be polarized along the direction of the applied magnetic field regardless of the ground state spin transition.

cond-mat.mes-hall↗

arXiv2002

Spontaneous Spin Coherence in n-GaAs Produced by Ferromagnetic Proximity Polarization

We find that photoexcited electrons in an n-GaAs epilayer rapidly (< 50 ps) spin-polarize due to the proximity of an epitaxial ferromagnetic metal. Comparison between MnAs/GaAs and Fe/GaAs structures reveals that this coherent spin polarization is aligned antiparallel and parallel to their magnetizations, respectively. In addition, the GaAs nuclear spins are dynamically polarized with a sign determined by the spontaneous electron spin orientation. In Fe/GaAs, competition between nuclear hyperfine and applied magnetic fields results in complete quenching of electron spin precession.

cond-mat.mes-hall↗