Nicholas G. Kioussis, The University Corporation, Northridge, DMR 0611562

1. Controlling the non-equilibrium interlayer exchange coupling (NEIEC) in asymmetric magnetic tunnel junctions (MTJ) Nicholas G. Kioussis, The University Corporation, Northridge, DMR 0611562 We have predicted an oscillatory bias behavior of the IEC in MTJ which can be selectively controlled via the asymmetry in band filling between the ferromagnetic leads. This can lead to a linear or quadratic low-bias behavior, including tuning the bias-induced reversal of IEC. These findings reconcile the apparently contradictory experimental results recently reported in the literature. The underlying mechanism for the NEIEC of non-collinear configurations is the interplay of four independent IEC for the majority- and minority spin bands of the leads solely in the ferromagnetic configuration. Supported by NSF-PREM grant DMR-0611562

2. Density gradient corrected Embedded Atom Method Nicholas G. Kioussis, The University Corporation, Northridge, DMR 0611562 Through detailed comparisons between EAM and first-principles calculations for Al, we find that EAM models tend to fail whenever there are large electron density gradients in the system, irrespective of specific atomic configurations. We attribute the observed EAM failures to the violation of the uniform density approximation (UDA) inherent to the EAM models. To remedy the insufficiency of UDA, we propose a gradient-corrected EAM model which introduces gradient corrections to the embedding function in terms of exchange-correlation and kinetic energy. Based on the perturbation theory of “quasiatoms” and density functional theory, the new embedding function captures the essential physics missing in UDA, and paves way for the development of more transferable EAM potentials. The research was supported by NSF-PREM grant DMR-0611562.