University of Minnesota
School of Physics & Astronomy

Condensed Matter Seminar

Thursday, April 3rd 2008
1:25 pm:
Condensed Matter Seminar in 210 Physics
Speaker: Saskia Fischer, University of Bochum
Subject: Spin-splitting and magneto-oscillations of mode-coupling

To date, the transport properties of spin-split one-dimensional (1D) subbands in coupled quantum wire systems with wave function hybridization (mode coupling) are widely unkown. We explore the magnetic field control and the influence of spin effects on mode coupling in short quantum wires with large 1D subband spacings (>10meV). Recently, we demonstrated the direct high-resolution energy spectroscopy of mode coupling [1] in such systems which allow a single-mode control. The access to spin-split transport channels and mode-coupled spin subbands may be of interest for spin-dependent quantum transport devices.

Here, we investigate 1D subbands, in particular for coupled modes, by tuning electric and magnetic fields. We observe, magnetooscillations of the energy splittings in tunnel-coupled 1DES with nearly identical 1D confinement in symmetric configuration in longitudinal magnetic fields [2], which are reproduced by an analytic expression [3]. In perpendicular magnetic fields we observe spin-split 1D subbands and strong indications of mode-coupling between spin split subbands in various asymmetric quantum wire configurations.

[1] S.F. Fischer et al., Nature Physics 2, 91 (2006).
[2] S.F. Fischer et al., Phys. Rev. B 74, 115324 (2006).
[3] L.G. Mourokh, Appl. Phys. Lett., 90, 132108 (2007).

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