This thesis describes magneto-optical processes in ferromagnetic (III,Mn)V semiconductors and their heterostructures induced by femtosecond laser pulses. Two-color ultrafast magneto-optical spectroscopy has been developed, which allows us to observe a rich array of dynamical phenomena that are absent in traditional nonmagnetic semiconductors or metallic/insulating magnets. We isolate several distinct temporal regimes in spin dynamics, interpreting the fast (< 1 ps) dynamics as spin heating through sp-d exchange interaction between photo-carriers and Mn ions while the ∼100 ps component as a manifestation of spin-lattice relaxation. Charge carrier and phonon dynamics were also carefully studied, showing an ultrashort charge lifetime of photoinjected electrons (∼ 2 ps) and propagating coherent acoustic phonon wavepackets with strongly probe energy dependent oscillation period, amplitude and damping.
| Identifer | oai:union.ndltd.org:RICE/oai:scholarship.rice.edu:1911/18989 |
| Date | January 2005 |
| Creators | Wang, Jigang |
| Contributors | Kono, Junichiro |
| Source Sets | Rice University |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 148 p., application/pdf |
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