TY  - JOUR
A1  - Margapoti, E.
A1  - Alves, F. M.
A1  - Mahapatra, S.
A1  - Lopez-Richard, V.
A1  - Worschech, L.
A1  - Brunner, K.
A1  - Qu, F.
A1  - Destefani, C.
A1  - Menendez-Proupin, E.
A1  - Bougerol, C.
A1  - Forchel, A.
A1  - Marques, G. E.
T1  - Paramagnetic shift in thermally annealed Cd\(_x\)Zn\(_{1-x}\)Se quantum dots
JF  - New Journal of Physics
N2  - The photoluminescence of annealed Cd\(_x\)Zn\(_{1-x}\)Se quantum dots (QDs) under the influence of an external magnetic field has been studied in this paper. Post-growth annealing was performed for different annealing times. Above a critical annealing time, the QD luminescence shows a pronounced red-shift of the Zeeman split magnetic subcomponents. This observation is in contrast to the blue-shift caused by the diamagnetic behavior that is usually observed in non-magnetic QDs. We attribute our finding to the paramagnetism caused by the mixing of heavy and light hole states. Hence, post-growth thermal annealing treatment might be employed to render undoped epitaxial QDs intrinsically magnetic in a controlled manner. Two theoretical models were developed: a few-particle model to account for excitonic complex effects and a multiband calculation that describes the valence band hybridization. Contrasting the two models allowed us to unambiguously elucidate the nature of such an effect.
KW  - semiconductors
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133294
VL  - 14
IS  - 043038
ER  - 
TY  - JOUR
A1  - Shamim, Saquib
A1  - Mahapatra, S.
A1  - Scappucci, G.
A1  - Klesse, W. M.
A1  - Simmons, M. Y.
A1  - Ghosh, Arindam
T1  - Dephasing rates for weak localization and universal conductance fluctuations in two dimensional Si: P and Ge: P δ-layers
JF  - Scientific Reports
N2  - We report quantum transport measurements on two dimensional (2D) Si:P and Ge:P δ-layers and compare the inelastic scattering rates relevant for weak localization (WL) and universal conductance fluctuations (UCF) for devices of various doping densities (0.3–2.5 × 10\(^{18}\)m\(^{−2}\)) at low temperatures (0.3–4.2 K). The phase breaking rate extracted experimentally from measurements of WL correction to conductivity and UCF agree well with each other within the entire temperature range. This establishes that WL and UCF, being the outcome of quantum interference phenomena, are governed by the same dephasing rate.
KW  - two-dimensional materials
KW  - quantum information
KW  - electronic properties and materials
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170934
VL  - 7
IS  - 46670
ER  -