Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 47: Quantendr
ähte und Korrelationseffekte

HL 47.8: Talk

Friday, March 12, 2004, 12:45–13:00, H15

Theoretical prediction of a transport quantum logic gate — •Matthias Sabathil and Peter Vogl — Walter Schottky Institut, TU Muenchen

We present a systematic theoretical study of the realization of a quantum logic gate based on a laterally structured high mobility 2DEG. The realistic electronic structure has been calculated solving the 3D Schroedinger-Poisson equation selfconsistently. For the prediction of the transport properties we used the recently developed contact block reduction (CBR) method that allows for the effiecient calculation of the ballistic transmission for large 3D devices with multiple leads.

In ballistic quantum devices, a single Qubit may be realized by electrons propagating within two adjacent quantum wires, representing the 0 and 1, respectively. Narrow windows in the barrier region between the wires act as beam splitters, allowing the 0 and 1 states to interfer. Additional gates are needed to control the phase shift within one of the wires. Here, we propose a Mach-Zender type interferometer based on an AlGaAs/GaAs high mobility 2DEG where the lateral confinement is produced by top gates. We find that this device can operate up to a temperature of several hundred mK. The calculations show a pronounced switching behavior as a function of the applied gate voltage.