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Báo cáo hóa học: " Temperature and electron density dependence of spin relaxation in GaAs/AlGaAs quantum well"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Temperature and electron density dependence of spin relaxation in GaAs/AlGaAs quantum well | Han et al. Nanoscale Research Letters 2011 6 84 http www.nanoscalereslett.eom content 6 1 84 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Temperature and electron density dependence of spin relaxation in GaAs AlGaAs quantum well Lifen Han Yonggang Zhu Xinhui Zhang Pingheng Tan Haiqiao Ni Zhichuan Niu Abstract Temperature and carrier density-dependent spin dynamics for GaAs AlGaAs quantum wells QWs with different structural symmetries have been studied by using time-resolved Kerr rotation technique. The spin relaxation time is measured to be much longer for the symmetrically designed GaAs QW comparing with the asymmetrical one indicating the strong influence of Rashba spin-orbit coupling on spin relaxation. D yakonov-Perel mechanism has been revealed to be the dominant contribution for spin relaxation in GaAs AlGaAs QWs. The spin relaxation time exhibits non-monotonic-dependent behavior on both temperature and photo-excited carrier density revealing the important role of non-monotonic temperature and density dependence of electron-electron Coulomb scattering. Our experimental observations demonstrate good agreement with recently developed spin relaxation theory based on microscopic kinetic spin Bloch equation approach. Introduction Spin dynamics and the related physics in semiconductors have drawn much attention in the past years because of its importance to realize novel spin-electronic devices 1 . In recent years electron spin relaxation in many types of materials especially in low dimensional III-V group semiconductor heterostructures has been studied extensively both theoretically and experimentally 1 . The relevant spin relaxation me chanisms such as the Elliott-Yafet Bir-Aranov-Pikus BAP and D yako-nov-Perel DP mechanisms as well as hyperfine interactions have been well established to describe spin relaxation and dephasing dynamics. However the relative importance of these mechanisms strongly depends on material design and .