636 research outputs found
Nanoscale electrical conductivity imaging using a nitrogen-vacancy center in diamond
The electrical conductivity of a material can feature subtle, nontrivial, and
spatially-varying signatures with critical insight into the material's
underlying physics. Here we demonstrate a conductivity imaging technique based
on the atom-sized nitrogen-vacancy (NV) defect in diamond that offers local,
quantitative, and noninvasive conductivity imaging with nanoscale spatial
resolution. We monitor the spin relaxation rate of a single NV center in a
scanning probe geometry to quantitatively image the magnetic fluctuations
produced by thermal electron motion in nanopatterned metallic conductors. We
achieve 40-nm scale spatial resolution of the conductivity and realize a
25-fold increase in imaging speed by implementing spin-to-charge conversion
readout of a shallow NV center. NV-based conductivity imaging can probe
condensed-matter systems in a new regime, and as a model example, we project
readily achievable imaging of nanoscale phase separation in complex oxides.Comment: Supplementary information at en
Imaging a Single-Electron Quantum Dot
Images of a single-electron quantum dot were obtained in the Coulomb blockade
regime at liquid He temperatures using a cooled scanning probe microscope
(SPM). The charged SPM tip shifts the lowest energy level in the dot and
creates a ring in the image corresponding to a peak in the Coulomb-blockade
conductance. Fits to the lineshape of the ring determine the tip-induced shift
of the electron energy state in the dot. SPM manipulation of electrons in
quantum dots promises to be useful in understanding, building and manipulating
circuits for quantum information processing.Comment: 14 pages including 3 figure
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