Colloquium

Imaging a Single-Electron Quantum Dot

Robert M. Westervelt
Harvard University
Wednesday, February 16, 2005
Higgins 310, 4 pm

Images of a quantum dot that contains only one electron were obtained at liquid-He temperatures using a cooled scanning probe microscope (SPM). Single-electron quantum dots are building blocks for quantum information processing systems. The dot was formed in a GaAs/AlGaAs heterostructure using surface gates. The charged SPM tip shifts the energy of the electron ground state in the dot and creates a ring in the image corresponding to a peak in its Coulomb-blockade conductance. Fits to the lineshape of the ring determine the tip-induced shift of the energy state. SPM manipulation of electrons in quantum dots promises to be useful for understanding, building and manipulating dot and dot circuits.

In collaboration with Parisa Fallahi, Ania Bleszynski, E.J. Heller, and A.C. Gossard.