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Akira Fukuda

Publications and source records attributed to Akira Fukuda.

2 recordsLinked to original sources
arXiv2013

Phase Transition to Insulating State from Quantum Hall State by Current-Induced Nuclear Spin Polarization

We investigate the resistance enhancement state (RES) where the magnetoresistance of the $ν= 2/3$ fractional quantum Hall state (FQHS) is increased with dynamic nuclear spin polarization (DNP) induced by a large electric current. After inducing DNP, we measure the temperature dependence of the magnetoresistance by a small current over a short period of time. We find that the FQHS makes a phase transition to an insulating state. By measuring the Hall resistance in the insulating state, we find that the RES exhibits a quantized Hall resistance. We discuss the RES in association with the Anderson localization.

cond-mat.mes-hall↗
arXiv2013

Interlayer Diffusion of Nuclear Spin Polarization in $ν=2/3$ Quantum Hall States

At the spin transition point of $ν=2/3$ quantum Hall states, nuclear spins in a two-dimensional electron gas are polarized by an electric current. Using GaAs/AlGaAs double-quantum-well samples, we first observed the spatial diffusion of nuclear spin polarization between the two layers when the nuclear spin polarization is current-induced in one layer. By numerical simulation, we estimated the diffusion constant of the nuclear spin polarization to be $15 \pm 7$\,nm$^2$/s.

cond-mat.mes-hall↗