Electronic structure of (In,Mn)As quantum dots buried in GaAs investigated by soft-x-ray ARPES
Journal article, 2016
Electronic structure of a molecular beam epitaxy-grown system of (In,Mn)As quantum dots (QDs) buried in GaAs is explored with soft-x-ray angle-resolved photoelectron spectroscopy (ARPES) using photon energies around 1 keV. This technique, ideally suited for buried systems, extends the momentum-resolving capabilities of conventional ARPES with enhanced probing depth as well as elemental and chemical state specificity achieved with resonant photoexcitation. The experimental results resolve the dispersive energy bands of the GaAs substrate buried in ?2 nm below the surface, and the impurity states (ISs) derived from the substitutional Mn atoms in the (In,Mn)As QDs and oxidized Mn atoms distributed near the surface. An energy shift of the Mn ISs in the QDs compared to (In,Mn)As DMS is attributed to the band offset and proximity effect at the interface with the surrounding GaAs. The absence of any ISs in the vicinity of the VBM relates the electron transport in (In,Mn)As QDs to the prototype (In,Mn)As diluted magnetic semiconductor. The SX-ARPES results are supported by measurements of the shallow core levels under variation of probing depth through photon energy. X-ray absorption measurements identify significant diffusion of interstitial Mn atoms out of the QDs towards the surface, and the role of magnetic circular dichroism is to block the ferromagnetic response of the (In,Mn)As QDs. Possible routes are drawn to tune the growth procedure aiming at practical applications of the (In,Mn)As based systems.
Mn)As
(In
quantum dots
magnetic properties
electronic structure
Author
A. D. Bouravleuv
St. Petersburg National Research University Academic of the Russian Academy of Sciences
Saint Petersburg State University
Russian Academy of Sciences
Ioffe Institute
L. L. Lev
National Research Centre "Kurchatov Institute"
Paul Scherrer Institut
C. Piamonteze
Paul Scherrer Institut
X. Wang
Paul Scherrer Institut
T. Schmitt
Paul Scherrer Institut
A. I. Khrebtov
St. Petersburg National Research University Academic of the Russian Academy of Sciences
Yu B. Samsonenko
St. Petersburg National Research University Academic of the Russian Academy of Sciences
Ioffe Institute
Russian Academy of Sciences
Janusz Kanski
Chalmers, Physics
G. E. Cirlin
Russian Academy of Sciences
Ioffe Institute
Saint Petersburg National Research University of Information Technologies, Mechanics and Optics University ITMO
St. Petersburg National Research University Academic of the Russian Academy of Sciences
V. N. Strocov
Paul Scherrer Institut
Nanotechnology
0957-4484 (ISSN) 1361-6528 (eISSN)
Vol. 27 42 425706-Subject Categories (SSIF 2011)
Atom and Molecular Physics and Optics
DOI
10.1088/0957-4484/27/42/425706