Regensburg 2007 – wissenschaftliches Programm

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SYSS: Symposium Spins in Semiconductors

SYSS 1: Spins in Semiconductors

SYSS 1.7: Hauptvortrag

Montag, 26. März 2007, 11:40–12:00, H1

Tailoring ferromagnetism in bulk semiconductors and quantum dots — •Igor Zutic — State University of New York at Buffalo

For dilute magnetic semiconductors to find wide application in real spintronic devices [1], their electronic and magnetic properties will require tailoring in much the same way that bandgaps are engineered in conventional semiconductors. In this talk, by using the density functional theory, we examine two examples: Mn-doped II-IV-V2 chalcopyrites [2] and Mn-doped II-VI quantum dots [3]. In the first case, we reveal a variation of magnetic properties across 64 different materials which cannot be explained by the dominant models of ferromagnetism in semiconductors. We identify a small number of novel stable chalcopyrites with excellent prospect for ferromagnetism. In the second case, we explore possibility of tailoring magnetism by controlling the electron-electron Coulomb interaction, without changing the number of particles. The interplay of strong Coulomb interactions and quantum confinement leads to enhanced inhomogeneous magnetization which persist at higher temperatures than in the non-interacting case. The temperature of the onset of magnetization can be controlled by changing the number of particles as well as by modifying the quantum confinement and the strength of Coulomb interactions.

Collaboration with S. C. Erwin (NRL), R. M. Abolfath (SUNY, Buffalo) and P. Hawrylak (NRC). Supported by the US ONR and NSF-ECCS CAREER.

[1] I. Zutic, J. Fabian, S. Das Sarma, Rev. Mod. Phys. 76, 323 (2004).

[2] S. C. Erwin and I. Zutic, Nature Mater., 3, 410 (2004).

[3] R. M. Abolfath, P. Hawrylak, and I. Zutic, cond-mat/0612489.