Subject Area B2: Spin and Charge Excitations in Ferromagnet-InAs Quantum-Dot Systems
Stefan Mendach, Daniela Pfannkuche
Manganese atoms in InAs act as acceptors. The spins of the itinerant holes couple the spins
of the localized manganese ions leading to dilute ferromagnetism in InAs.
In this subject area we want to describe the influence of manganese on the
energy spectra of self-assembled InAs quantum dots. The energy levels of
few-particles quantum dots will be calculated by exact diagonalization techniques.
In particular the magnetization of single quantum dots and arrays of quantum dots
will be studied. The bandstructure of InAs including spin-orbit interaction
will be considered by a k∑p approach.
Special attention will be paid to the optical response and the temporal development
of spin states in excited quantum dots.
The theoretical results will
be compared with experimental results from microphotoluminescence.
J. van Bree, P. M. Koenraad, and J. Fernández-Rossier,
(a) Picture of self-assembled quantum dots taken with an atomic-force microscope.
(b) Capacitance-voltage curve indicating the electron population of quantum dots.
"Single-exciton spectroscopy of single Mn doped InAs quantum dots",
Phys. Rev. B 78, 165414-1-165414-14 (2008).
J. Fernández-Rossier and L. Brey,
"Ferromagnetism Mediated by Few Electrons in a Semimagnetic Quantum Dot"
Phys. Rev. Lett. 93, 117201-1-117201-4 (2004).
T. Brocke, M.-T. Bootsmann, M. Tews, B. Wunsch, D. Pfannkuche, Ch. Heyn,
W. Hansen, D. Heitmann, and C. Schüller,
"Spectroscopy of few-electron collective excitations in charge-tunable artificial atoms",
Phys. Rev. Lett. 91, 257401-1-257401-4 (2003).
Magnetism and spin excitations in Mn-doped InAs quantum dots
Microphotoluminescence of manganese-doped InAs quantum dots with tunable strain