TY  - THES
A1  - Margapoti, Emanuela
T1  - Optical properties of thermally annealed CdZnSe/ZnSe quantum dots
N2  - see: pdf-file
N2  - siehe: pdf-Dokument
KW  - Physik
KW  - CdZnSe/ZnSe
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-52946
ER  - 
TY  - JOUR
A1  - Rothe, D. G.
A1  - Reinthaler, R. W.
A1  - Liu, C-X
A1  - Molenkamp, L. W.
A1  - Zhang, S-C
A1  - Hankiewicz, E. M.
T1  - Fingerprint of different spin-orbit terms for spin transport in HgTe quantum wells
N2  - Using k · p theory, we derive an effective four-band model describing the physics of the typical two-dimensional topological insulator (HgTe/CdTe quantum well (QW)) in the presence of an out-of-plane (in the z-direction) inversion breaking potential and an in-plane potential. We find that up to third order in perturbation theory, only the inversion breaking potential generates new elements to the four-band Hamiltonian that are off-diagonal in spin space. When this new effective Hamiltonian is folded into an effective twoband model for the conduction (electron) or valence (heavy hole) bands, two competing terms appear: (i) a Rashba spin–orbit interaction originating from inversion breaking potential in the z-direction and (ii) an in-plane Pauli term as a consequence of the in-plane potential. Spin transport in the conduction band is further analysed within the Landauer–Büttiker formalism. We find that for asymmetrically doped HgTe QWs, the behaviour of the spin-Hall conductance is dominated by the Rashba term.
KW  - Physik
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68362
ER  - 
TY  - JOUR
A1  - Schenkel, Alexander
A1  - Uhlemann, Christoph F.
T1  - Field Theory on Curved Noncommutative Spacetimes
N2  - We study classical scalar field theories on noncommutative curved spacetimes. Following the approach of Wess et al. [Classical Quantum Gravity 22 (2005), 3511 and Classical Quantum Gravity 23 (2006), 1883], we describe noncommutative spacetimes by using (Abelian) Drinfel’d twists and the associated ?-products and ?-differential geometry. In particular, we allow for position dependent noncommutativity and do not restrict ourselves to the Moyal–Weyl deformation. We construct action functionals for real scalar fields on noncommutative curved spacetimes, and derive the corresponding deformed wave equations. We provide explicit examples of deformed Klein–Gordon operators for noncommutative Minkowski, de Sitter, Schwarzschild and Randall–Sundrum spacetimes, which solve the noncommutative Einstein equations. We study the construction of deformed Green’s functions and provide a diagrammatic approach for their perturbative calculation. The leading noncommutative corrections to the Green’s functions for our examples are derived.
KW  - Physik
KW  - noncommutative field theory
KW  - Drinfel’d twists
KW  - deformation quantization
KW  - field theory on curved spacetimes
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68648
ER  -