Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 35: HL Poster II

HL 35.74: Poster

Wednesday, April 3, 2019, 17:30–20:00, Poster E

Electron and Nuclear Spin Interaction in n-GaAs: Impact of Doping and Temperature — •Lida Abaspour, Pavel Serin, Jan Gerrit Lonnemann, Eddy Rugeramigabo, Jens Hübner, and Michael Oestreich — Institute for Solid State Physics, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany

The mutual interaction of nuclear and electron spins in semiconductors has been identified as a major source of nuclear and electron spin relaxation (SR). Doping-dependent optical measurements and magneto-transport of the electron SR time in n-doped bulk GaAs structures reveal competing SR mechanisms (variable range hopping (VRH), hyperfine interaction (HF) and the Dyakonov Perel effect (DP)) below and around the metal to insulator transition (MIT) [1, 2]. At the onset of the transition to the DP effect, temperature-dependent measurements show the effect of non-degenerate DP for higher temperatures while VRH and HF affect the SR at low temperature.

Moreover, we measure the doping dependence of the nuclear spin dynamics for different n-GaAs samples. The number of localized electrons increases with increasing doping concentration below the MIT where hyperfine interaction reduces the SR time. In the metallic regime, delocalized electrons reduce the SR time. Furthermore, for the lowest doped sample, temperature dependent measurements allow distinguishing the mutual impact of the different mechanism involved.

[1] R. I. Dzhioev, et. al., Phys. Rev. B 66, 245204 (2002).

[2] J. G. Lonnemann, et. al., Phys. Rev. B 96, 045201 (2017).