AVS 49th International Symposium
    Electronic Materials and Devices Monday Sessions
       Session EL+SC+MI-MoM

Invited Paper EL+SC+MI-MoM10
Electronic Structure and Spin-Polarization of Mn-containing Dilute Magnetic III-V Semiconductors

Monday, November 4, 2002, 11:20 am, Room C-107

Session: Semiconductors
Presenter: L. Kronik, University of Minnesota
Authors: L. Kronik, University of Minnesota
M. Jain, University of Minnesota
J.R. Chelikowsky, University of Minnesota
Correspondent: Click to Email
The systematic use of electron spin, in addition to its charge, holds great promise for a new class of semiconductor devices with unprecedented functionality. Recently, Mn-containing, "dilute magnetic", III-V semiconductors have emerged as candidate materials for such a technology. They can potentially produce charge carriers with well-defined spin, yet are compatible with already existing semiconductor technologies. In order to assess the performance limits of such materials theoretically, we present first principles pseudopotential - density functional calculations for the electronic structure of the dilute magnetic semiconductors Mn@sub x@Ga@sub 1-x@As and and Mn@sub x@Ga@sub 1-x@N, with an experimentally relevant realistic x=0.063, in their ordered ferromagnetic phase. We predict that both materials allow, in principle, for a theoretical limit of 100% spin-injection, and that spin-polarized transport can be attained in both materials in the context of a simple band picture. This is because in MnGaAs, hybridization of As 4p and Mn 3d orbitals splits the valence band, resulting in a ~0.5 eV energy range where holes have a well-defined spin and an effective mass comparable to that of GaAs. In MnGaN, the situation is even more favorable: hybridization of Mn 3d and N 2p orbitals results in the formation of a ~1.5 eV wide impurity band, which supports effective mass transport. We will discuss the technological impact of these findings and compare our results to pertinent experimental data.