13,557 research outputs found
Electron mobility in surface- and buried- channel flatband In<sub>0.53</sub>Ga<sub>0.47</sub>As MOSFETs with ALD Al<sub>2</sub>O<sub>3</sub> gate dielectric.
In this paper, we investigate the scaling potential of flatband III-V MOSFETs by comparing the mobility of surface and buried In<sub>0.53</sub>Ga<sub>0.47</sub>As channel devices employing an Atomic Layer Deposited (ALD) Al<sub>2</sub>O<sub>3</sub> gate dielectric and a delta-doped InGaAs/InAlAs/InP heterostructure.
Peak electron mobilities of 4300 cm<sup>2</sup>/V·s and 6600 cm<sup>2</sup>/V·s at a carrier density of 3×1012 cm<sup>-2</sup> for the surface and buried channel structures respectively were determined. In contrast to similarly scaled inversion-channel devices, we find that mobility in surface channel flatband structures does not drop rapidly with electron density, but rather high mobility is maintained up to carrier concentrations around 4x10<sup>12</sup> cm<sup>-2</sup> before slowly dropping to around 2000 cm<sup>2</sup>/V·s at 1x10M<sup>13</sup> cm<sup>-2</sup>. We believe these to be world leading metrics for this material system and an important development in informing the III-V MOSFET device architecture selection process for future low power, highly scaled CM
Possible evidence of non-Fermi liquid behavior from quasi-one-dimensional indium nanowires
We report possible evidence of non-Fermi liquid (NFL) observed at room
temperature from the quasi one-dimensional (1D) indium (In) nanowires
self-assembled on Si(111)-77 surface. Using high-resolution
electron-energy-loss spectroscopy, we have measured energy and width
dispersions of a low energy intrasubband plasmon excitation in the In
nanowires. We observe the energy-momentum dispersion (q) in the low q
limit exactly as predicted by both NFL theory and the
random-phase-approximation. The unusual non-analytic width dispersion measured with an exponent =1.400.24, however,
is understood only by the NFL theory. Such an abnormal width dispersion of low
energy excitations may probe the NFL feature of a non-ideal 1D interacting
electron system despite the significantly suppressed spin-charge separation
(40 meV).Comment: 11 pages and 4 figure
Pseudogap of metallic layered nickelate R2-xSrxNiO4 (R=Nd, Eu) crystals measured using angle-resolved photoemission spectroscopy
We have investigated charge dynamics and electronic structures for single
crystals of metallic layered nickelates, R2-xSrxNiO4 (R=Nd, Eu), isostructural
to La2-xSrxCuO4. Angle-resolved photoemission spectroscopy on the
barely-metallic Eu0.9Sr1.1NiO4 (R=Eu, x=1.1) has revealed a large hole surface
of x2-y2 character with a high-energy pseudogap of the same symmetry and
comparable magnitude with those of underdoped (x<0.1) cuprates, although the
antiferromagnetic interactions are one order of magnitude smaller. This finding
strongly indicates that the momentum-dependent pseudogap feature in the layered
nickelate arises from the real-space charge correlation.Comment: 4 pages, 4 figures. Accepted in Physical Review Letter
Sr2+ binding to the Ca2+ binding site of the synaptotagmin 1 C2B domain triggers fast exocytosis without stimulating SNARE interactions
Sr2+ triggers neurotransmitter release similar to Ca2+, but less efficiently. We now show that in synaptotagmin 1 knockout mice, the fast component of both Ca2+- and Sr2+-induced release is selectively impaired, suggesting that both cations partly act by binding to synaptotagmin 1. Both the C(2)A and the C2B domain of synaptotagmin 1 bind Ca2+ in phospholipid complexes, but only the C2B domain forms Sr2+/phospholipid complexes; therefore, Sr2+ binding to the C2B domain is sufficient to trigger fast release, although with decreased efficacy. Ca2+ induces binding of the synaptotagmin C, domains to SNARE proteins, whereas Sr2+ even at high concentrations does not. Thus, triggering of the fast component of release by Sr2+ as a Ca2+ agonist involves the formation of synaptotagmin/ phospholipid complexes, but does not require stimulated SNARE binding
Electronic inhomogeneity in EuO: Possibility of magnetic polaron states
We have observed the spatial inhomogeneity of the electronic structure of a
single-crystalline electron-doped EuO thin film with ferromagnetic ordering by
employing infrared magneto-optical imaging with synchrotron radiation. The
uniform paramagnetic electronic structure changes to a uniform ferromagnetic
structure via an inhomogeneous state with decreasing temperature and increasing
magnetic field slightly above the ordering temperature. One possibility of the
origin of the inhomogeneity is the appearance of magnetic polaron states.Comment: 4 pages, 3 figure
Two-dimensional cellular automaton model of traffic flow with open boundaries
A two-dimensional cellular automaton model of traffic flow with open
boundaries are investigated by computer simulations. The outflow of cars from
the system and the average velocity are investigated. The time sequences of the
outflow and average velocity have flicker noises in a jamming phase. The low
density behavior are discussed with simple jam-free approximation.Comment: 14 pages, Phys. Rev. E in press, PostScript figures available at
ftp://hirose.ai.is.saga-u.ac.jp/pub/documents/papers/1996/2DTR/
OpenBoundaries/Figs.tar.g
Thermal Radiation from Nucleons and Mesons
Thermal photon emission rates due to meson-nucleon interactions have been
evaluated. An exhaustive set of reactions involving p(\bar p), n(\bar n), rho,
omega, a_1, pi and eta is seen to provide a sizeable contribution to the
emission rate from hot hadronic matter. Contributions from baryonic resonances
are found to be negligibly small
Spectroscopic signatures of a bandwidth-controlled Mott transition at the surface of 1T-TaSe
High-resolution angle-resolved photoemission (ARPES) data show that a
metal-insulator Mott transition occurs at the surface of the quasi-two
dimensional compound TaSe. The transition is driven by the narrowing of the
Ta band induced by a temperature-dependent modulation of the atomic
positions. A dynamical mean-field theory calculation of the spectral function
of the half-filled Hubbard model captures the main qualitative feature of the
data, namely the rapid transfer of spectral weight from the observed
quasiparticle peak at the Fermi surface to the Hubbard bands, as the
correlation gap opens up.Comment: 4 pages, 4 figures; one modified figure, added referenc
Capillary Filling of Anodized Alumina Nanopore Arrays
The filling behavior of a room temperature solvent,
perfluoromethylcyclohexane, in approximately 20 nm nanoporous alumina membranes
was investigated in situ with small angle x-ray scattering. Adsorption in the
pores was controlled reversibly by varying the chemical potential between the
sample and a liquid reservoir via a thermal offset, T. The system
exhibited a pronounced hysteretic capillary filling transition as liquid was
condensed into the nanopores. These results are compared with Kelvin-Cohan
theory, with a modified Derjaguin approximation, as well as with predictions by
Cole and Saam.Comment: 4 pages, 3 figures, pre-proof
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