Electronic Structure of Magnetic Semiconductor CdCr_2Te_4: A Possible Spin-Dependent Symmetry Filter

Abstract: We present a theoretical investigation of the electronic and magnetic structure of spinel CdCr_2Te_4 using density functional theory, its extensions via onsite Hubbard U interactions, and a screened-hybrid-functional exchange potential. We find that the ground state is semiconducting within the latter approach, and within this magnetic-semiconducting system we compute the complex band structure, finding a slowly decaying evanescent $\tilde{\Delta}_1$ state possibly suitable for realizing a spin-dependent symmetry filter effect.