Regensburg 2007 – wissenschaftliches Programm

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SYSS: Symposium Spins in Semiconductors

SYSS 1: Spins in Semiconductors

SYSS 1.4: Hauptvortrag

Montag, 26. März 2007, 10:40–11:00, H1

Driven coherent oscillations of a single electron spin in a quantum dot — •Frank Koppens, Christo Buizert, Klaas-Jan Tielrooij, Ivo Vink, Katja Nowack, Tristan Meunier, Leo Kouwenhoven, and Lieven Vandersypen — Kavli Institute of Nanoscience, Delft, Netherlands

The ability to control the quantum state of a single electron spin in a quantum dot is at the heart of recent developments towards a scalable spin-based quantum computer. In combination with the recently demonstrated controlled exchange gate between two neighbouring spins, driven coherent single spin rotations would permit universal quantum operations. In this talk, I will discuss the experimental realization of single electron spin rotations in a gate-defined GaAs double quantum dot. We coherently control the quantum state of the electron spin by applying short bursts of an on-chip generated oscillating magnetic field. This allows us to observe up to eight Rabi oscillations of the electron spin in a microsecond burst. Via Ramsey-type pulse sequences we measure an apparent time-averaged coherence time which is limited by the hyperfine interaction with the nuclear spins. We erase these nuclear spin effects to a large extend via spin-echo pulse sequences and recover the intrinsic coherence time.