%0 Journal Article
%T Spin Relaxation in Germanium Nanowires
%A Ashish Kumar
%A M. W. Akram
%A Bahniman Ghosh
%J ISRN Nanomaterials
%D 2012
%R 10.5402/2012/207043
%X We use semiclassical Monte Carlo approach along with spin density matrix calculations to model spin polarized electron transport. The model is applied to germanium nanowires and germanium two-dimensional channels to study and compare spin relaxation between them. Spin dephasing in germanium occurs because of Rashba Spin Orbit Interaction (structural inversion asymmetry) which gives rise to the DĄŻyakonov-Perel (DP) relaxation. In germanium spin flip scattering due to the Elliot-Yafet (EY) mechanism also leads to spin relaxation. The spin relaxation tests for both 1D and 2D channels are carried out at different values of temperature and driving electric field, and the variation in spin relaxation length is recorded. Spin relaxation length in a nanowire is found to be much higher than that in a 2D channel due to suppression of DP relaxation in a nanowire. At lower temperatures the spin relaxation length increases. This suggests that spin relaxation in germanium occurs slowly in a 1D channel (nanowires) and at lower temperatures. The electric field dependence of spin relaxation length was found to be very weak. 1. Introduction Of late, intensive experimental and theoretical studies have been conducted on the physics of electron spins due to the enormous promise displayed by the spin-based devices [1]. Spin transport in semiconductors has been continuously investigated due to the possibility of integration of spintronics with semiconductor technology. This integration has attracted huge research interest due to its prospects [2¨C5] in implementing novel devices that can operate at much less power levels and higher processing speeds. Spintronics-based devices thus promise highly improved performance over their contemporary electronic counterparts. The suitability of present semiconductor materials in spintronic-based applications needs to be established to bring about successful integration of the two and to be able to achieve the advantages listed above. The basic idea of the spintronic-based devices is to use the spin degree of freedom. At the source, information is encoded as spin state of individual electrons and is then injected into the material. During its motion in the material, the electrons undergo scattering and hence the electron spin states relax or depolarize as they move in the channel. This is the process of spin relaxation. Spin detection is done at the drain. Our paper here deals with the second process of spin relaxation in a material. Spin relaxation lengths or spin dephasing lengths represent the distance from the source in which the spin
%U http://www.hindawi.com/journals/isrn.nanomaterials/2012/207043/