Traditional high efficiency spin-polarized electron sources (SPES) consist mainly of binary or pseudobinary zinc-blende GaAs based materials, whereas their ternary analogs II-IV-V2 (II=Zn, Cd, IV=Si, Ge, Sn, and V=As) as well as II-VI ternary analogs I-III-VI2 (I=Cu, Ag, III=Al, Ga, In, and VI=Se) have not drawn wide attention because their crystal field splitting ΔCF near the valence band maximum is either negative or close to zero in their ground state chalcopyrite structure. Using first-principles calculations, we show that some derivative quaternary I-III-II2 -VI4 and II-IV-III2 -V4 compounds can have coherent ground state stannite or kesterite structures with large and positive ΔCF due to their increased chemical and structural flexibility. We propose that ZnSiAl2 As4 and CdGeAl2 As4 in the stannite structure, and ZnSnGa2 As4 and CuAlCd 2Se4 in the kesterite structure could be good candidate SPES materials with high polarization and quantum efficiency.
Bibliographical noteFunding Information:
The work in Fudan is partially supported by the National Sciences Foundation of China, the Basic Research Program of MOE and Shanghai, and the Special Funds for Major State Basic Research. Computations were performed in the Supercomputer Center of FU and CCS. The work at NREL is funded by the U.S. Department of Energy under Contract No. DE-AC36-08GO28308.