First principles transport calculations of spin transport at Cu/Cr and Cu/V interfaces

Efficient transmission of spin currents is crucial to the operation of many spintronic devices. While the transmission of spin currents in metals depends on the spin diffusion length, the behavior of spin currents near interfaces has escaped description using a single parameter. A recent experimental study shows that heterostructures containing Cu(001)/Cr(001) and Cu(001)/V(001) layers strongly reflect spin currents regardless of the magnetic ground states of Cr (antiferromagnet) and V (paramagnet). To elucidate the physical origin of the peculiar behavior, we model the reflection and transmission of spin currents incident to both interfaces using first-principles calculations. Specifically, our calculations utilize density functional theory (DFT) as implemented in Quantum Espresso followed by Wannier interpolation using Wannier90 to express each system in maximally-localized Wannier functions (MLWF) basis. We then compute the scattering matrices using Green's function approaches to quantify the reflection and transmission of spin currents given an incoming spin current. Our results expand the functionality of magnetic heterostructures as modulators of spin currents, potentially providing a useful tool in the development of spintronic devices.