Walter Schottky Institute
Center for Nanotechnology and Nanomaterials

Welcome to the Brandt group
Group leader: Prof. Dr. Martin Brandt

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Decoherence in self-assembled quantum dots

Quantum dots are another type of artificial atom which can be realized in semiconductors. Such dots form naturally e.g. when thin layers of InGaAs are grown on GaAs. Self-organized quantum dots are already used commercially in light emitting diodes, but are still subject to intense investigations of their fundamental physical properties. One interesting aspect is the fact that single electrons or holes can be stored in these quantum dots for very long times. Using circularly polarized light for the excitation of the quantum dot, the electron or hole can be created with a specific spin state which, notably, also survives for hundreds of microseconds. For the application of these spin states in quantum information processing, also their decoherence has to be slow compared to the clock rate of future processors. We study the spin decoherence in quantum dots using pulsed magnetic resonance techniques and develop new methods to efficiently read out the spin state of single charge carriers in quantum dots.

Brandt 1

Selected publications

  • Observation of extremely slow hole spin relaxation in self-assembled quantum dots
    Physical Review B 76, 241306 (2007)
    D. Heiss, S. Schaeck, H. Huebl, M. Bichler, G. Abstreiter, J. J. Finley, D. V. Bulaev, D. Loss

  • Spintronics: Information Processing with Spins
    WSI Book (2008)



DFG via SFB 631 “Solid-State Quantum Information Processing”, Teilprojekt C6 “Coherent Control of Electron and Hole Spin Qubits in Quantum Dots and Molecules Using Microwave Fields”.

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