Spin Dynamics in the Second Subband of a Quasi Two Dimensional System Studied in a Single Barrier Heterostructure by Time Resolved Kerr Rotation - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




Spin Dynamics in the Second Subband of a Quasi Two Dimensional System Studied in a Single Barrier Heterostructure by Time Resolved Kerr Rotation - Condensed Matter > Mesoscale and Nanoscale Physics - Download this document for free, or read online. Document in PDF available to download.

Abstract: By biasing a single barrier heterostructure with a 500nm-thick GaAs layer asthe absorption layer, the spin dynamics for both of the first and secondsubband near the AlAs barrier are examined. We find that when simultaneouslyscanning the photon energy of both the probe and pump beams, a sign reversal ofthe Kerr rotation KR takes place as long as the probe photons break away thefirst subband and probe the second subband. This novel feature, while stemmingfrom the exchange interaction, has been used to unambiguously distinguish thedifferent spin dynamics $T 2^{1*}$ and $T 2^{2*}$ for the first and secondsubbands under the different conditions by their KR signs negative for$1^{st}$ and positive for $2^{nd}$. In the zero magnetic field, by scanningthe wavelength towards the short wavelength, $T 2^{1*}$ decreases in accordancewith the D-yakonov-Perel- DP spin decoherence mechanism. At 803nm,$T 2^{2*}$450ps becomes ten times longer than $T 2^{1*}$50ps. However, thevalue of $T 2^{2*}$ at 803nm is roughly the same as the value of $T 2^{1*}$ at815nm. A new feature has been disclosed at the wavelength of 811nm under thebias of -0.3V 807nm under the bias of -0.6V that the spin coherence times$T 2^{1*}$ and $T 2^{2*}$ and the effective $g^*$ factors $|g^*E1|$ and$|g^*E2|$ all display a sudden change, due to the -resonant- spin exchangecoupling between two spin opposite bands.



Author: F. Zhang, H. Z. Zheng, Y. Ji, J. Liu, G. R. Li

Source: https://arxiv.org/







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