Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 63: Poster: Quantum Dots and Optics

HL 63.26: Poster

Wednesday, March 22, 2017, 15:00–19:00, P1A

Nuclear Spin Relaxation in n-type GaAs — •lida abaspour, jan gerrit lonnemann, eddy patrick rugeramigabo, jens hübner, and michael oestreich — Institute for Solid States Physics, Leibniz University of Hannover, Germany

The intriguing mutual interaction of nuclear and electron spins in semiconductors [1] has been identified as a major source of nuclear as well as electron spin relaxation. Their relative impact significantly depends on the doping density which determines the degree of localization and the density of free electrons. The nuclear spin diffusion is governed by the interaction with electron spins of localized impurities [2] and delocalized conduction band electrons [3], respectively. Here, we investigate the detailed impact of doping density on the nuclear spin relaxation by all optical Hanle depolarization. The n-type MBE-grown GaAs samples cover two orders of magnitude around the metal to insulator transition. Consequently, we are able to precisely determine the effects of dipole-dipole type and carrier mediated nuclear spin diffusion. Moreover, the technique allowed us to investigate the complex interaction with the spin of electrons either localized to impurities or constrained to a confining impurity band.

[1] F. Berski et al., Phys. Rev. Lett. 115, 176601, (2015).

[2] M. Kotur et al., Phys. Rev. B 94, 081201(R) (2016).

[3] M. Kotur et al., JETP Lett. 99, 37 (2014).