Hall‐effect determination of the N‐trap bound state in GaAs1−xPx

1977 ◽  
Vol 31 (10) ◽  
pp. 685-687 ◽  
Author(s):  
L. J. van Ruyven ◽  
H. J. A. Bluyssen ◽  
R. W. van der Heijden ◽  
T. B. Tan ◽  
H. I. Ralph
Keyword(s):  
Hall Effect ◽  
Bound State

scholarly journals Gating Competence of Constitutively Open CLC-0 Mutants Revealed by the Interaction with a Small Organic Inhibitor

2003 ◽  
Vol 122 (3) ◽  
pp. 295-306 ◽  
Author(s):  
Sonia Traverso ◽  
Laura Elia ◽  
Michael Pusch
Keyword(s):  
Chloride Channels ◽  
Bound State ◽  
Side Chain ◽  
Pore Channel ◽  
Kinetic Properties ◽  
Wild Type ◽  
High Affinity ◽  
Critical Residue ◽  
Fast Gating

Opening of CLC chloride channels is coupled to the translocation of the permeant anion. From the recent structure determination of bacterial CLC proteins in the closed and open configuration, a glutamate residue was hypothesized to form part of the Cl−-sensitive gate. The negatively charged side-chain of the glutamate was suggested to occlude the permeation pathway in the closed state, while opening of a single protopore of the double-pore channel would reflect mainly a movement of this side-chain toward the extracellular pore vestibule, with little rearrangement of the rest of the channel. Here we show that mutating this critical residue (Glu166) in the prototype Torpedo CLC-0 to alanine, serine, or lysine leads to constitutively open channels, whereas a mutation to aspartate strongly slowed down opening. Furthermore, we investigated the interaction of the small organic channel blocker p-chlorophenoxy-acetic acid (CPA) with the mutants E166A and E166S. Both mutants were strongly inhibited by CPA at negative voltages with a >200-fold larger affinity than for wild-type CLC-0 (apparent KD at −140 mV ∼4 μM). A three-state linear model with an open state, a low-affinity and a high-affinity CPA-bound state can quantitatively describe steady-state and kinetic properties of the CPA block. The parameters of the model and additional mutagenesis suggest that the high-affinity CPA-bound state is similar to the closed configuration of the protopore gate of wild-type CLC-0. In the E166A mutant the glutamate side chain that occludes the permeation pathway is absent. Thus, if gating consists only in movement of this side-chain the mutant E166A should not be able to assume a closed conformation. It may thus be that fast gating in CLC-0 is more complex than anticipated from the bacterial structures.

Illuminating the proton radius conundrum: the μHe+ Lamb shiftThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

2011 ◽  
Vol 89 (1) ◽  
pp. 47-57 ◽  
Author(s):  
A. Antognini ◽  
F. Biraben ◽  
J. M.R. Cardoso ◽  
D. S. Covita ◽  
A. Dax ◽  
...  
Keyword(s):  
Nuclear Polarization ◽  
Bound State ◽  
Atomic Systems ◽  
Charge Radii ◽  
Polarization Contribution ◽  
Proton Radius ◽  
Nuclear Rms Charge Radii ◽  
Proton Radius Puzzle ◽  
Bound State Qed

We plan to measure several 2S–2P transition frequencies in μ4He+ and μ3He+ by means of laser spectroscopy with an accuracy of 50 ppm. This will lead to a determination of the corresponding nuclear rms charge radii with a relative accuracy of 3 × 10−4, limited by the uncertainty of the nuclear polarization contribution. First, these measurements will help to solve the proton radius puzzle. Second, these very precise nuclear radii are benchmarks for ab initio few-nucleon theories and potentials. Finally when combined with an ongoing measurement of the 1S–2S transition in He+, these measurements will lead to an enhanced bound-state QED test of the 1S Lamb shift in He+.

Determination of the Germanium Acceptor Ionisation Energy of ALGai-^As (0 ^ * ^ 0.40) by Hall Effect and Luminescence

1989 ◽  
pp. 257-267
Author(s):  
G. Oelgart ◽  
B Lippold ◽  
R . Heilmann ◽  
H . Neumann ◽  
B . Jacobs
Keyword(s):  
Hall Effect ◽  
Ionisation Energy

ENERGY SPECTRA OF GLUINONIUM

2011 ◽  
Vol 20 (supp02) ◽  
pp. 200-209
Author(s):  
CÉSAR A. Z. VASCONCELLOS ◽  
DIMITER HADJIMICHEF ◽  
MÁRIO L. L. DA SILVA ◽  
MOISÉS RAZEIRA ◽  
ALEXANDRE MESQUITA ◽  
...  
Keyword(s):  
Energy Spectrum ◽  
Excited States ◽  
Bound States ◽  
Bound State ◽  
State Equation ◽  
Relativistic Case ◽  
Light Scalar ◽  
Pseudo Scalar ◽  
Relativistic Bound States

We investigate relativistic bound states for a hypothetical light scalar gluino pair (gluinonium), in the framework of the covariant Bethe-Salpeter equation (BSE). In this paper, we derive, from the covariant BSE for a fermion-anti-fermion system, using charge conjugation, the corresponding bound-state equation for a gluino pair and we then formulate, for a static harmonic kernel, the coupled differential equations for the corresponding static Bethe-Salpeter amplitude. The steps of our approach then include a numerical solution of the Bethe-Salpeter amplitude for a two-body interaction consisting of scalar, pseudo-scalar, and four-vector components and the determination of the energy spectrum for the ground and the radially excited states of massive gluinonium. We found the energy spectrum and radial distributions of fundamental and excited states of gluinonium. The comparison of the values obtained in the extreme relativistic case with the corresponding values predicted by a harmonic oscillator potential model shows that there is good agreement between the two formulations. The predictions of the binding energy of glunionium in the non-relativistic model are however systematically higher.

scholarly journals Determination of the resistivity anisotropy ofSrRuO3by measuring the planar Hall effect

2007 ◽  
Vol 75 (12) ◽  
Author(s):  
Isaschar Genish ◽  
Lior Klein ◽  
James W. Reiner ◽  
M. R. Beasley
Keyword(s):  
Hall Effect ◽  
Planar Hall Effect ◽  
Resistivity Anisotropy

Far-infrared magnetooptical generalized ellipsometry determination of free-carrier parameters in semiconductor thin film structures

2002 ◽  
Vol 744 ◽  
Author(s):  
Tino Hofmann ◽  
Marius Grundmann ◽  
Craig M. Herzinger ◽  
Mathias Schubert ◽  
Wolfgang Grill
Keyword(s):  
Hall Effect ◽  
Dielectric Function ◽  
Far Infrared ◽  
Free Carrier ◽  
Independent Experiment ◽  
Electron Mass ◽  
Effective Electron Mass ◽  
Effective Electron ◽  
Infrared Wavelengths

ABSTRACTIn accord with the Drude model, the free-carrier contribution to the dielectric function at infrared wavelengths is proportional to the ratio of the free-carrier concentration N and the effective mass m*, and the product of the optical mobility μ and m*. Typical infrared optical experiments are therefore sensitive to the free-carrier mass, but determination of m* from the measured dielectric function requires an independent experiment, such as an electrical Hall-effect measurement, which provides either N or μ. Highly-doped zincblende III-V-semiconductors exposed to a strong external magnetic field exhibit non-symmetric magnetooptical birefringence, which is inversely proportional to m*. If the spectral dependence of the magnetooptical dielectric function tensor is known, the parameters N, m* and μ can be determined independently from optical measurements alone. Generalized ellipsometry measures three complex-valued ratios of normalized Jones matrix elements, from which the individual tensor elements of the dielectric function of arbitrarily anisotropic materials in layered samples can be reconstructed. We present the application of generalized ellipsometry to semiconductor layer structures at far-infrared wavelengths, and determine the magnetooptical dielectric function for n-GaAs and n-AlGaInP for wavelengths from 100 μm to 15 μm. We obtain the effective electron mass and mobility results of GaAs in excellent agreement with results obtained from Hall-effect and Shubnikov-de-Haas experiments. The effective electron mass in disordered n-AlGaInP obtained here is in very good agreement with previous k·p calculations. (Far)-infrared magnetooptic generalized ellipsometry may open up new avenues for non-destructive characterization of free-carrier properties in complex semiconductor heterostructures.

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