Real-space pseudopotential calculations of spin-dependent electron transport in magnetic molecular junctions

A real-space pseudopotential approach is developed to calculate the spin-dependent transport in nanoscale junctions. Our method is based on self-consistent solution of the Kohn-Sham equation of density functional theory with asymptotic boundary conditions. This method is applied to a simple magnetic molecule, the Sc dimer, bridging nonmagnetic, planar jellium electrodes for a series of molecule-lead spacing. We find that the spin-dependent conductance within this formalism is rather robust over a wide range of electronic coupling parameters. The minority channel of parallel-aligned Sc₂ produces a fairly stable conductance of roughly half of a quantum unit (e²∕h). Other systems show sensitive dependence on the coupling strength. Atomic origins of the dependence are discussed.