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Hindi Review Article, J Nanomater Mol Nanotechnol Vol: 3 Issue: 4
Electronic Theory of Ultrafast Spin Dynamics in NiO
| Chun Li1, Georgios Lefkidis1,2* and Wolfgang Hübner2 | |
| 1School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xi'an 710072, China | |
| 2Department of Physics and Research Center OPTIMAS, Kaiserslautern University of Technology, PO Box 3049, 67653, Kaiserslautern, Germany | |
| Corresponding author : Georgios Lefkidis Department of Physics and Research Center OPTIMAS, Kaiserslautern University of Technology, PO Box 3049, 67653, Kaiserslautern, Germany Tel: +49 631 205 3207 E-mail: lefkidis@physik.uni-kl.de |
|
| Received: September 02, 2014 Accepted: October 06, 2014 Published: October 10, 2014 | |
| Citation: Li C, Lefkidis G, Hübner W (2014) Electronic Theory of Ultrafast Spin Dynamics in NiO. J Nanomater Mol Nanotechnol 3:4. doi:10.4172/2324-8777.1000151 |
Abstract
Electronic Theory of Ultrafast Spin Dynamics in NiO
NiO is a good candidate for ultrafast magnetic switching because of its large spin density, antiferromagnetic order, and clearly separated intragap states. In order to detect and monitor the switching dynamics, we develop a systematic approach to study optical second harmonic generation (SHG) in NiO, both at the (001) surface and in the bulk. In our calculations NiO is modeled as a doubly embedded cluster. All intragap d-states of the bulk and the (001) surface are obtained with highly-correlational quantum chemistry and propagated in time under the influence of a static magnetic field and a laser pulse. We find that demagnetization and switching can be best achieved in a subpicosecond regime with linearly rather than circularly polarized light. We also show the importance of including an external magnetic field in order to distinguish spin-up and spin-down states and the necessity of including magnetic-dipole transitions in order to realize the process in the centrosymmetric bulk. Having already shown the effects of phonons in the SHG for the bulk NiO within the frozen-phonon approximation, and following the same trail of thoughts, we discuss the role of phonons in a fully quantized picture as a symmetrylowering mechanism in the switching scenario and investigate the electronic and lattice temperature effects.
