Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 11: Poster 1
HL 11.79: Poster
Montag, 11. März 2002, 17:00–19:30, Poster A
Anisotropic Spin Splitting in InAs Quantum Dots — •I. Hapke-Wurst1, U.F. Keyser1, U. Zeitler1, R.J. Haug1, K. Pierz2 und Z. Ma2 — 1Inst. f. Festkörperphysik, Universität Hannover, Appelstr. 2, 30167 Hannover — 2PTB, Bundesallee 100, 38116 Braunschweig
We have performed magneto-transport measurements through self-assembled InAs quantum dots embedded in an AlAs barrier. IV-characteristics measured at T= 1.3 K show steps due to resonant tunneling through single dots.
In a magnetic field we observe Zeeman splitting of these steps. For fields applied parallel to the current we deduce g factors from the voltage difference of the spin split steps of g=0.7−1.4 for several dots with decreasing dot size. Increasing the angle between the magnetic field and the current direction leads to an increase of the g factor up to 30 % for fields perpendicular to the current [1]. The anisotropy is due to the stronger confinement in the growth plane with respect to the confinement parallel to the growth axis.
For tilting the magnetic field in the growth plane we observe a change in the g factor of about 10% for two different crystallographic axes [2]. This anisotropy hints at a slightly elongated shape of the dots as observed by Ballet et al. [3].
[1] J.M. Meyer et al., phys. stat. sol. b 224, 685 (2001).
[2] I. Hapke-Wurst et al., Physica E, in press.
[3] P. Ballet et al., Appl. Phys. Lett. 75, 337 (1999).