539 research outputs found
Doping effect on the evolution of the pairing symmetry in n-type superconductor near antiferromagnetic phase boundary
We present the investigation results of the in-plane \{rho}(T) resistivity
tensor at the temperature range 0.4-40 K in magnetic fields up to 90kOe (H||c,
J||ab) for electron-doped Nd{2-x}Ce{x}CuO{4+{\delta}} with different degree of
disorder near antiferromagnetic - superconducting phase boundary. We have
experimentally found that for optimally doped compound both the upper critical
field slope and the critical temperature decrease with increasing of the
disorder parameter (d-wave pairing) while in the case of the underdoped system
the critical temperature remains constant and (dHc2/dT)|Tc increases with
increasing of the disorder (s-wave pairing). These features suggest a possible
implementation of the complex mixture state as the (s+id)-pairing.Comment: 9 pages, 2 figure
Effect of exchange electron-electron interaction on conductivity of InGaAs single and double quantum wells in ballistic regime
We report an experimental study of quantum conductivity corrections for
two-dimensional electron gas in a GaAs/InGaAs/GaAs single and double quantum
wells in a wide temperature range (1.8-100) K. We perform a comparison of our
experimental data for the longitudinal conductivity at zero magnetic field to
the theory of interaction-induced corrections to th transport coefficients. In
the temperature range from 10 K up to (45-60) K, wich covers the ballistic
interaction regimes for our samples, a rather good agreement between the theory
and our experimental results has been found
Involvement of uncoupled antenna chlorophylls in photoinhibition in thylakoids
AbstractEvidence is presented, by means of both fluorescence and action spectroscopy, that a small, spectroscopically heterogeneous population of both Chl a and Chl b molecules is present in isolated spinach thylakoids and is active in photoinhibition. The broadness of the action spectrum suggests that degraded or incompletely assembled pigment–protein complexes may be involved
Parabolic negative magnetoresistance in p-Ge/Ge1-xSix heterostructures
Quantum corrections to the conductivity due to the weak localization (WL) and
the disorder-modified electron-electron interaction (EEI) are investigated for
the high-mobility multilayer p-Ge/Ge1-xSix heterostructures at T = (0.1 -
20.0)K in magnetic field B up to 1.5T. Negative magnetoresistance with
logarithmic dependence on T and linear in B^2 is observed for B >= 0.1T. Such a
behavior is attributed to the interplay of the classical cyclotron motion and
the EEI effect. The Hartree part of the interaction constant is estimated
(F_/sigma = 0.44) and the WL and EEI contributions to the total quantum
correction /Delta /sigma at B = 0 are separated (/Delta /sigma_{WL} ~ 0.3/Delta
/sigma; /Delta /sigma_{EEI} ~ 0.7/Delta /sigma).Comment: 3 pages, 4 figure
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