Diameter dependence of spin relaxation in SiGe nanowires

In this paper, we use 1-D semi classical Monte Carlo Method to investigate spin polarized transport in SiGe nanowires (SiGeNWs) having Ge mole fraction 0.3. We use a multi-subbands semi classical Monte Carlo approach to model spin dephasing. Monte Carlo simulations have been widely adopted to study electron transport in devices and have recently been used in conjunction with spin density matrix calculations to model spin transport. Spin dephasing in SiGeNWs is caused due to D´yakonov-Perel (DP) relaxation and due to Elliott-Yafet (EY) relaxation. The spin polarization is studied along the length of the SiGeNWs. The ensemble averaged spin components variation has been studied for SiGeNWs along the nanowires length. The effect of variation of nanowires diameter on spin dephasing length has been studied. It is found that as the diameter of nanowires increases spin dephasing length also increases and become saturated beyond some value of diameter, this is due to the reduction in surface roughness scattering, which is a dominant contributor to the total scattering rate.