2010/10/26 by Restrepo, Oscar D., Windl, Wolfgang · 1 citation
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
paper · doi:10.48550/arxiv.1010.5436
We present a generally applicable parameter-free first-principles method to determine electronic spin relaxation times and apply it to the technologically important group-IV materials silicon, diamond and graphite. We concentrate on the Elliott-Yafet mechanism, where spin relaxation is induced by momentum scattering off phonons and impurities. In silicon, we find a ∼ T-3 temperature dependence of the phonon-limited spin relaxation time T1 and a value of 4.3 ns at room temperature, in agreement with experiments. For the phonon-dominated regime in diamond and graphite, we predict a stronger ∼ T-5 and ∼ T-4.5 dependence that limits T1 (300 K) to 180 and 5.8 ns, respectively. A key aspect of this study is that the parameter-free nature of our approach provides a method to study the effect of \em any type of impurity or defect on spin-transport. Furthermore we find that the spin-mix amplitude in silicon does not follow the Eg-2 band gap dependence usually assigned to III-V semiconductors but follows a much weaker and opposite Eg0.67 dependence. This dependence should be taken into account when constructing silicon spin transport models.