Charge and spin transport over record distances in GaAs metallic n -type nanowires

H. Hijazi , D. Paget , Guillaume Monier (1) , G. Grégoire , J. Leymarie , E. Gil , F. Cadiz , C. Robert-Goumet , Y. André

1 IP - Institut Pascal

We have investigated charge and spin transport in n-type metallic GaAs nanowires (≈ 10 17 cm −3 doping level), grown by hydride vapor phase epitaxy (HVPE) on Si substrates. For this doping level, charge and spin transport might appear difficult because of the expected localization of minority holes in the valence band potential fluctuations generated by statistical fluctuations of the donor concentration. In contrast with these expectations, it is found, using spatially-and spectrallyresolved investigation of the luminescence intensity and circular polarization under laser excitation, that charge can be transported over record distances larger than 25 µm at 6K. Establishment of a charge thermodynamic equilibrium between the photoelectrons and the Fermi sea occurs over a distance from the excitation spot of 2 µm. At this distance, the spin polarization is still observed, implying that photoelectrons have preserved their spin orientation and that the two spin reservoirs remain distinct. Spatially-resolved Investigations show that a photoelectron spin polarization of 20% can even be transported over a record distance of more than 20 µm. This finding has potential applications for long distance spin transport in n-type doped nanowires.

Domaines: Matière Condensée [cond-mat]

H. Hijazi, D. Paget, Guillaume Monier, G. Grégoire, J. Leymarie, et al.. Charge and spin transport over record distances in GaAs metallic n -type nanowires. Physical Review B, 2021, 103 (19), ⟨10.1103/PhysRevB.103.195314⟩. ⟨hal-03431182⟩