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Lecture Saskia F. Fisher


21 December 2004 FWN-Building 5113.0202, Nijenborgh 4, 9747 AG, Groningen
Speaker: Dr. Saskia F. Fisher
Affiliation: Ruhr-Universität Bochum, Germany
Title: Mode coupling of spatially coincident electron wave guides
Date: Tue Dec 21, 2004
Start: 15.00
Location: FWN-Building 5113.0202
Host: B.J. van Wees
Telephone: +31 50 363 4933


Coupling phenomena of electron wave guides are meaningful for the general understanding of two-level systems as well as for future applications in quantum information processing. Wave function mixing and splitting of degenerate energy levels are an outcome of mode coupling of one-dimensional (1D) electron systems. Nanolithography with an atomic force microscope enables us to prepare ballistic 1D electron systems with high 1D-subband separations (>10 meV), for which coupling-induced energy splittings can be experimentally resolved. We investigate spatially coincident 1D electron systems for which massive wave function mixing is expected. Such a case is given by quantum point contacts fabricated from a modulation doped GaAs/AlGaAs system with a 30 nm wide square quantum well with two occupied 2D subbands. Recording transconductance maxima at 2 K as a function of gate voltage and magnetic field reveals a rich mode spectrum. Magnetotransport spectroscopy of unprecedented resolution allows the direct determination of splitting energies of anticrossings (> 2 meV).
Last modified:22 October 2012 2.31 p.m.