1,975 research outputs found
A photometric investigation of Comet P/Encke
A photometric investigation of Comet P/Encke was undertaken using the 2.2 m telescope and the 0.6 m telescope. The two primary scientific objectives were: (1) measurement of the production rates of OH, CN, C3, and C2 as a function of heliocentric distance; and (2) determination of the comet's rotational period by searching for periodic brightness variations in the inner coma. Synoptic observation in the Canary Islands; Cambridge, Massachusetts; Flagstaff, Arizona; and Mauna Kea were planned for the study of the comet's rotation
Lifshitz Transition in Underdoped Cuprates
Recent studies show that quantum oscillations thought to be associated with a
density wave reconstructed Fermi surface disappear at a critical value of the
doping for YBa2Cu3O6+y, and the cyclotron mass diverges as the critical value
is approached from the high doping side. We argue that the phenomenon is due to
a Lifshitz transition where the pockets giving rise to the quantum oscillations
connect to form an open (quasi-1d) Fermi surface. The estimated critical doping
is close to that found by experiment, and the theory predicts a logarithmic
divergence of the cyclotron mass with a coefficient comparable to that observed
in experiment.Comment: 4 pages, 4 figure
Antiphase Stripe Order as the Origin of Electron Pockets Observed in 1/8-Hole-Doped Cuprates
Recent quantum oscillation measurements on underdoped cuprates are shown to
be consistent with the predictions of a mean field theory of the 1/8 magnetic
antiphase stripe order proposed to occur in high- cuprates. In particular,
for intermediate values of the stripe order parameter, the magneto-transport is
found to be dominated by an electron pocket
Theory of Mott insulator/band insulator heterostructure
A theory of heterostructures comprised of LaTiO (a Mott insulator) and
SrTiO (a band insulator) is presented. The band structure of the Ti %
-electrons is treated with a nearest neighbor tight-binding approximation; the
electric fields arising from the La/Sr charge difference and the
carriers are treated within a Hartree approximation; and the on-site
interactions are treated by unrestricted Hartree-Fock. The phase diagram as a
function of interaction strength and layer number is determined and predictions
are made for optical conductivity experiments. A note worthy finding is that
the edges of the heterostructure are generally metallic.Comment: 11 pages, 9 figure
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