4,351 research outputs found
Distribution function of persistent current
We introduce a variant of the replica trick within the nonlinear sigma model
that allows calculating the distribution function of the persistent current. In
the diffusive regime, a Gaussian distribution is derived. This result holds in
the presence of local interactions as well. Breakdown of the Gaussian
statistics is predicted for the tails of the distribution function at large
deviations
Diamagnetic response of Aharonov-Bohm rings: Impurity backward scatterings
We report a theoretical calculation on the persistent currents of disordered
normal-metal rings. It is shown that the diamagnetic responses of the rings in
the vicinity of the zero magnetic field are attributed to multiple backward
scatterings off the impurities. We observe the transition from the paramagnetic
response to the diamagnetic one as the strength of disorder grows using both
the analytic calculation and the numerical exact diagonalization.Comment: final versio
Influence of trigonal warping on interference effects in bilayer graphene
Bilayer graphene (two coupled graphitic monolayers arranged according to Bernal stacking) is a two-dimensional gapless semiconductor with a peculiar electronic spectrum different from the Dirac spectrum in the monolayer material. In particular, the electronic Fermi line in each of its valleys has a strong p -> -p asymmetry due to trigonal warping, which suppresses the weak localization effect. We show that weak localization in bilayer graphene may be present only in devices with pronounced intervalley scattering, and we evaluate the corresponding magnetoresistance
Reliable method for testing gross leaks in semiconductor component packages
Simple, reliable, inexpensive method for gross-leak testing has been devised, based upon the conventional fine-leak technique. The sensitivity ranges from the detection of very large leaks down to leaks of 10 to the minus seven cc helium per sec
Differential identities for parametric correlation functions in disordered systems
Copyright © 2008 The American Physical Society.We derive a family of differential identities for parametric correlation functions in disordered systems by casting them as first- or second-order Ward identities of an associated matrix model. We show that this approach allows for a systematic classification of such identities, and provides a template for deriving higher-order results. We also reestablish and generalize some identities of this type which had been derived previously using a different method
Orifice gross leak tester Patent
Test chambers with orifice and helium mass spectrometer for detecting leak rate of encapsulated semiconductor device
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