45 research outputs found
Polaronic signature in the metallic phase of La0.7Ca0.3MnO3 films detected by scanning tunneling spectroscopy
In this work we map tunnel conductance curves with nanometric spatial
resolution, tracking polaronic quasiparticle excitations when cooling across
the insulator-to-metal transition in La0.7Ca0.3MnO3 films. In the insulating
phase the spectral signature of polarons, a depletion of conductance at low
bias flanked by peaks, is detected all over the scanned surface. These features
are still observed at the transition and persist on cooling into the metallic
phase. Polaron-binding energy maps reveal that polarons are not confined to
regions embedded in a highly-conducting matrix but are present over the whole
field of view both above and below the transition temperature.Comment: 10 pages, 4 figure
Quantum Information Processing with Ferroelectrically Coupled Quantum Dots
I describe a proposal to construct a quantum information processor using
ferroelectrically coupled Ge/Si quantum dots. The spin of single electrons form
the fundamental qubits. Small (<10 nm diameter) Ge quantum dots are optically
excited to create spin polarized electrons in Si. The static polarization of an
epitaxial ferroelectric thin film confines electrons laterally in the
semiconductor; spin interactions between nearest neighbor electrons are
mediated by the nonlinear process of optical rectification. Single qubit
operations are achieved through "g-factor engineering" in the Ge/Si structures;
spin-spin interactions occur through Heisenberg exchange, controlled by
ferroelectric gates. A method for reading out the final state, while required
for quantum computing, is not described; electronic approaches involving single
electron transistors may prove fruitful in satisfying this requirement.Comment: 10 pages, 3 figure
Piezoelectric response of epitaxial Pb(Zr0.2Ti0.8)O3 films measured by scanning tunneling microscopy
Assessing the Capabilities of Sentinel-1 and 2 for Citywide Slum Mapping with Machine Learning
info:eu-repo/semantics/nonPublishe
Size-dependent light emission from mass-selected clusters.
The emission of photons in the visible wavelength range from
mass-selected Ag+_n, Cu+_n, Pt+_n and Pd+_n () clusters is observed. Photons are detected
≈ 10-4 s after the cluster generation in a sputter
source. The emission intensities display distinct variations with
cluster size and material. The observations are interpreted in
terms of the decay of metastable states which are excited during the
high-energy sputtering process used for the generation of these
clusters