M. Talanana

Graphite and graphene as perfect spin filters

Based upon the observations (i) that their in-plane lattice constants match almost perfectly and (ii) that their electronic structures overlap in reciprocal space for one spin direction only, we predict perfect spin filtering for interfaces between graphite and (111) fcc or (0001) hcp Ni or Co. The spin filtering is quite insensitive to roughness and disorder. The formation of a chemical bond between graphite and the open d-shell transition metals that might complicate or even prevent spin injection into a single graphene sheet can be simply prevented by dusting Ni or Co with one or a few monolayers of Cu while still preserving the ideal spin-injection property.

Orientation-Dependent Transparency of Metallic Interfaces

As devices are reduced in size, interfaces start to dominate electrical transport, making it essential to be able to describe reliably how they transmit and reflect electrons. For a number of nearly perfectly lattice-matched materials, we calculate from first principles the dependence of the interface transparency on the crystal orientation. Quite remarkably, the largest anisotropy is predicted for interfaces between the prototype free-electron materials silver and aluminum, for which a massive factor of 2 difference between (111) and (001) interfaces is found.

Pd/Ag and Pd/Au interface specific resistances and interfacial spin flipping

We measured the specific resistances, 2ARPd∕Ag and 2ARPd∕Au (sample area A times resistance R), and spin-flip probabilities δPd∕Ag and δPd∕Au for Pd/Ag and Pd/Au interfaces with current perpendicular to the interfaces. 2ARPd∕Ag=0.7±0.15fΩm2 and 2ARPd∕Au=0.45±0.15fΩm2 are smaller than our revised estimate of 2ARPd∕Cu=0.85±0.15fΩm2, and lie further from no-free-parameter calculations. Our estimates of δPd∕Ag=0.15±0.08 and δPd∕Ag=0.08±0.08 are less than our prior estimate of δPd∕Cu∼0.24.