Electronic structure of (In,Mn)As quantum dots buried in GaAs investigated by soft-x-ray ARPES
Artikel i vetenskaplig tidskrift, 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.

quantum dots

electronic structure

Mn)As

magnetic properties

(In

Författare

A. D. Bouravleuv

Russian Academy of Sciences

Saint Petersburg State University - Spsu

L. L. Lev

Paul Scherrer Institut

National Research Centre "Kurchatov Institute"

C. Piamonteze

Paul Scherrer Institut

X. Wang

Paul Scherrer Institut

T. Schmitt

Paul Scherrer Institut

A. I. Khrebtov

Russian Academy of Sciences

Yu B. Samsonenko

Russian Academy of Sciences

Janusz Kanski

Chalmers, Fysik

G. E. Cirlin

Russian Academy of Sciences

ITMO University

V. N. Strocov

Paul Scherrer Institut

Nanotechnology

0957-4484 (ISSN) 1361-6528 (eISSN)

Vol. 27 42 425706-

Ämneskategorier

Atom- och molekylfysik och optik

DOI

10.1088/0957-4484/27/42/425706

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Senast uppdaterat

2018-07-04