Computational design of a material for high-efficiency spin-polarized electron source

The search for the highest quality and efficient spin-polarized electron source (SPES) is of fundamental importance in the investigation of spin-dependent phenomena in atomic, condensed-matter, nuclear, and particle physics. We propose a material, AgGaSe2 in the CuAu phase, as a high-quality SPES. We show that AgGaSe2 in the CuAu phase has an "ideal" band structure that allows the generation of electron beams with 100% polarization: a direct band gap with large and positive spin-orbit splitting and crystal-field splitting. Moreover, we predict that strain-free AgGaSe2 in CuAu phase can be obtained by epitaxial growth on ZnSe substrate. (C) 2002 American Institute of Physics.