Subject Area B2: Spin and Charge Excitations in FerromagnetInAs QuantumDot Systems
Stefan Mendach, Daniela Pfannkuche
(a) Picture of selfassembled quantum dots taken with an atomicforce microscope.
(b) Capacitancevoltage curve indicating the electron population of quantum dots.
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 selfassembled InAs quantum dots. The energy levels of
fewparticles 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 spinorbit 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. FernándezRossier,
"Singleexciton spectroscopy of single Mn doped InAs quantum dots",
Phys. Rev. B 78, 165414116541414 (2008).
J. FernándezRossier and L. Brey,
"Ferromagnetism Mediated by Few Electrons in a Semimagnetic Quantum Dot"
Phys. Rev. Lett. 93, 11720111172014 (2004).
T. Brocke, M.T. Bootsmann, M. Tews, B. Wunsch, D. Pfannkuche, Ch. Heyn,
W. Hansen, D. Heitmann, and C. Schüller,
"Spectroscopy of fewelectron collective excitations in chargetunable artificial atoms",
Phys. Rev. Lett. 91, 25740112574014 (2003).
Magnetism and spin excitations in Mndoped InAs quantum dots
Microphotoluminescence of manganesedoped InAs quantum dots with tunable strain
