Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 57: Spintronics/Quantum information: Materials and methods (HL, jointly with TT)

HL 57.6: Vortrag

Mittwoch, 13. März 2013, 16:15–16:30, H2

Influence of strong quantum confinement on the magnetic dopant-carrier exchange coupling in Mn²⁺ doped CdSe nanoribbons — Rachel Fainblat¹, •Franziska Muckel¹, Julia Frohleiks¹, Jung Ho Yu², Jiwoong Yang², Taeghwan Hyeon², and Gerd Bacher¹ — ¹Werkstoffe der Elektrotechnik and CeNIDE, Universität Duisburg-Essen, Germany — ²Nanomaterials Laboratory, Seoul National University, Korea

Key materials for future spintronic applications might be magnetically doped semiconductors with a substantial coupling between the dopants and charge carriers of the host semiconductor. This interaction is expected to be significantly altered by quantum confinement, an issue which is controversially discussed since more than a decade.

Here, we report on a clear evidence of a quantum confinement induced modification of both, s-d and s-p exchange interaction in two dimensional 1.4 nm thick Mn²⁺ doped CdSe quantum nanoribbons [1]. Both absorption and magnetic circular dichroism spectra are dominated by spectrally well-separated resonance peaks related to the heavy and the light hole excitonic transition. This allows a separate study of the s-d and the p-d exchange interaction constants. Taking into account the optical selection rules and the statistical orientation of the nanoribbons on the substrate, a remarkable change of the s-d exchange constant with respect to bulk is indicated. Room-temperature studies revealed an unusually high effective g-factor up to ∼13 encouraging the implementation of the nanoribbons for spintronic applications.

[1] R. Fainblat et al., Nano Letters 12, 5311 (2012)