Electron spin dynamics are studied in Ga-doped ZnO single crystals by time-resolved Faraday and Kerr rotation spectroscopies. Long-lived spin coherence with two dephasing processes is discovered where the characteristic time is up to 5.2 ns at room temperature. Through the dependence measurements of laser wavelength and temperature, the room-temperature long-lived spin signal is attributed to localized electrons. The spin dephasing (relaxation) processes are independent of transverse (longitudinal) magnetic fields, indicating the spin dephasing not resulting from the $g$-factor inhomogeneity and electron-nuclear hyperfine interaction. Phonon-induced spin dephasing/relaxation mechanism is also excluded by the magnetic field and temperature dependence measurements. It reveals that the two spin dephasing processes originate from two types of localized electrons, both of which are dominated by the anisotropic exchange Dzyaloshinskii-Moriya interaction between adjacent localized electrons.

Close

PrevNext

View figure in article

• Optical generation of spin carriers
• Spin dynamics
• Spin relaxation
• Doped semiconductors
• II-VI semiconductors
• Magneto-optical Kerr effect
• Ultrafast pump-probe spectroscopy