Two-electron transport in a quantum waveguide having a single Anderson impurity

We consider the scattering problem of two-electron transport in onedimensional channel coupled with an Anderson-type impurity. The treatment includes the backscattering of the electrons. We show that the transport properties are fundamentally different for spin singlet and triplet states, thus the impurity acts as a novel filter that operates based on the total spin angular momentum of the electron pairs, but not individual spins. The filter provides a deterministic generation of electron entanglement in spin, as well as energy and momentum space.