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HL: Halbleiterphysik

HL 11: Poster 1

HL 11.77: Poster

Montag, 11. März 2002, 17:00–19:30, Poster A

Spin-splitting in electron channels in the one-dimensional quantum limit — •Ilaria Pallecchi, Jörg Lohse, Christian Heyn, and Wolfgang Hansen — Institut für Angewandte Physik, Universität Hamburg

We study the behavior of 1D systems in GaAs/AlGaAs heterostructures, whose filling is controlled by field effect. Confining potential is defined by fork-shaped interdigital metallic gates having lithographic width ∼ 150 nm, realized by e-beam lithography. By means of phase sensitive measurements of the sample differential capacitance, we are able to control the filling of single 1D subbands and investigate the thermodynamic and tunneling DOS. The development of a structure related to spin splitting is studied as a function of both magnetic field and confinement. At the lowest 1D confinements, we find an enhanced g-factor, up to a factor of almost 50 larger than the No-dqbareNo-dq value. With increasing confinement, the g-factor is progressively suppressed. The observations are explained by theoretical models in terms of competition between exchange interactions and kinetic energy of edge electrons.

This project is supported by the DFG via SFB 508 No-dqQuantum MaterialsNo-dq and by the EU via the TMR programme.