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Indirect Exciton (indirect + exciton)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Strong coupling in artificial semimagnetic Cd(Mn,Mg)Te quantum dot molecule

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 15 2006
S. V. Zaitsev
Abstract Exciton photoluminescence in a pair of strongly coupled artificial asymmetric quantum dots (QDs) has been studied in a magnetic field up to 8 T. The QD molecules have been fabricated by a selective interdiffusion technique applied to asymmetric semimagnetic CdTe/Cd(Mg,Mn)Te double quantum wells. The lateral confinement potential within the plane, induced by the diffusion, gives rise to effective zero-dimensional exciton localization. In contrast to a typically positive exciton Lande g -factor, an exciton transition in the non-magnetic QD demonstrates a nearly zero g -factor, indicating a strong electron tunnel coupling between the QDs. The strong coupling results in the formation of an inter-QDs indirect exciton, which is a ground exciton state at high magnetic field, as found in the experiment and confirmed by our calculations. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Indirect absorption edge of TlGaSe2 crystals

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2006
Vytautas Grivickas
Abstract Absorption spectra of high-quality layered TlGaSe2 single crystals were measured in a wide temperature range. Results obtained at low temperatures show that the direct excitonic absorption initiating at EGdir = 2.127 eV is perturbed by several series of step-like features inherent for the indirect type transitions. Spectral modelling of these features revealed that: (i) the ground state of indirect exciton, n = 1, has a large Rydberg energy of about 100 meV, and (ii) the enhanced absorption to excited indirect excitonic states, n = 2, 3, exceeds the classical prediction for scaling factors K1ind/n3. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Photoluminescence and in-plane diffusion of indirect excitons

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2005
L. E. Smallwood
Abstract In-plane spatial diffusion of indirect excitons in GaAs/AlGaAs coupled quantum wells (QWs) is studied theoretically. In spatial photoluminescence (PL) diagrams obtained from experiments, two rings of PL appear around the excitation spot, and their size and intensity depend upon the lattice temperature Tb and the optical pump intensity. We explain and model numerically the first PL ring, by using coupled nonlinear equations for the diffusion, thermalization and optical decay of the excitons. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]