Spin extraction theory and its relevance to spintronics

Extraction of electrons from a semiconductor to a ferromagnet as well as the case of injection in the reverse direction may be formulated as a scattering theory. However, the presence of bound states at the interface arising out of doping on the semiconductor side must be taken into account in the scattering theory. Inclusion of the interface states yields an explanation of a recent result of spin imaging measurement which contradicts the current understanding of spin extraction. The importance of an extraction theory to spintronics is illustrated by an application to a spin switch.Comment: 4 two column pages, 3 figures, major revisions to improve the presentation. in addition, the new version includes an electrically controlled spin switc

Large Higgs-electron Yukawa coupling in 2HDM

The present upper bound on $\kappa_e$, the ratio between the electron Yukawa coupling and its Standard Model value, is of ${\cal O}(600)$. We ask what would be the implications in case that $\kappa_e$ is close to this upper bound. The simplest extension that allows for such enhancement is that of two Higgs doublet models (2HDM) without natural flavor conservation. In this framework, we find the following consequences: (i) Under certain conditions, measuring $\kappa_e$ and $\kappa_V$ would be enough to predict values of Yukawa couplings for other fermions and for the $H$ and $A$ scalars. (ii) In the case that the scalar potential has a softly broken $Z_2$ symmetry, the second Higgs doublet must be light, but if there is hard breaking of the symmetry, the second Higgs doublet can be much heavier than the electroweak scale and still allow the electron Yukawa coupling to be very different from its SM value. (iii) CP must not be violated at a level higher than ${\cal O}(0.01/\kappa_e)$ in both the scalar potential and the Yukawa sector. (iv) LHC searches for $e^+e^-$ resonances constrain this scenario in a significant way. Finally, we study the implications for models where one of the scalar doublets couples only to the first generation, or only to the third generation.Comment: 14 pages, 2 figure

Hiring in the age of social media: new rules, new game

Companies are beginning to bypass traditional agency channels with new in-house recruitment practices, new executive search entities are challenging existing models, and individuals are using novel pathways to reach out to prospective employers. This is one of the areas of interest for a team of researchers and industry partners in the University of Sydney’s Digital Disruption Research Group (DDRG), which is looking at fundamental changes that are occurring in business as a result of digital technologies. In this study, we worked alongside a large, global professional services firm to understand the impact of social media on corporate recruitment, and to identify ways in which the recruitment processes can be effectively managed for better quality outcomes