AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Tuesday Sessions
       Session NS+EM-TuM

Invited Paper NS+EM-TuM5
Spin Physics in Few-Electron Quantum Dots

Tuesday, November 1, 2005, 9:40 am, Room 210

Session: Nanoscale Electronic Devices & Detection
Presenter: L. Kouwenhoven, Delft University of Technology, The Netherlands
Correspondent: Click to Email
Few-electron quantum dots are realized in various semiconductor materials. The conventional system for transport studies is an AlGaAs/GaAs heterostructure in which quantum dots are defined by surface gates. We have studied the spin states in one and two-electron dots. The spin states are resolved in a magnetic field that splits the one-electron spin states and also the triplet states for two electrons. We manipulate the spin states using a pulse technique that allows to determine the spin of individual electrons. As a spin off we measure the spin relaxation times under various circumstances (e.g. magnetic field). The obtained time scales are in good agreement with theory based on spin-orbit and hyperfine interaction. A new class of materials are semiconductor nanowires. We have fabricated quantum dot devices in InP and InAs wires with diameters around 50 nm. We observe discrete states and resolve Zeeman splitting of the spin states in a magnetic field. In addition we have used superconducting contacts to bias the nanowires with supercurrents.