Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 2: Spin Phenomena in Semiconductors
HL 2.2: Vortrag
Montag, 5. September 2022, 10:00–10:15, H31
Interplay of spin-orbit coupling and spin diffusion on spin helices lifetime in GaAs quantum wells — •Sergiu Anghel1, Karl Schiller1, Go Yusa2,3, Takaaki Mano4, Takeshi Noda4, and Markus Betz1 — 1Experimentelle Physik 2, Technische Universität Dortmund, Otto-Hahn-Straße 4a, D-44227 Dortmund — 2Department of Physics, Tohoku University, Sendai 980-8578, Japan — 3Center for Spintronics Research Network, Tohoku University, Sendai 980-8578, Japan — 4National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan
This work reveals the dependence of the persistent spin helix (PSH) lifetime on spin diffusion coefficient and the electron density, by employing time-resolved magneto-optical Kerr effect microscopy to study the spin polarization evolution in low-dimensional GaAs QWs. It is shown that for the achieving the longest PSH lifetime, the variation of scattering rate with the electron density is of higher importance than the fulfilling of the persistent spin helix condition when the Rashba α and Dresselhaus β parameters are balanced (suppression of D’yakanov-Perel spin dephasing mechanism). More specifically, the PSH relaxation rate is determined mostly by the spin diffusion coefficient that depends on electron density nonmonotonously. The longest experimentally observed PSH lifetime occurs at an electron density, corresponding to the transition from Boltzmann to Fermi-Dirac statistics - several times higher than that when the persistent spin helix is expected. These facts highlight the role the electron density may play when considering applications for spintronic devices.