4 research outputs found
Universal relation between longitudinal and transverse conductivities in quantum Hall effect
We show that any critical transition region between two adjacent Hall
plateaus in either integer or fractional quantum Hall effect is characterized
by a universal semi-circle relationship between the longitudinal and transverse
conductivities, provided the sample is homogeneous and isotropic on a large
scale. This conclusion is demonstrated both for the phase-coherent quantum
transport as well as for the incoherent transport.Comment: REVTEX 3.0, 1 figure, 4 pages. SISSA-08179
Universal flow diagram for the magnetoconductance in disordered GaAs layers
The temperature driven flow lines of the diagonal and Hall magnetoconductance
data (G_{xx},G_{xy}) are studied in heavily Si-doped, disordered GaAs layers
with different thicknesses. The flow lines are quantitatively well described by
a recent universal scaling theory developed for the case of duality symmetry.
The separatrix G_{xy}=1 (in units e^2/h) separates an insulating state from a
spin-degenerate quantum Hall effect (QHE) state. The merging into the insulator
or the QHE state at low temperatures happens along a semicircle separatrix
G_{xx}^2+(G_{xy}-1)^2=1 which is divided by an unstable fixed point at
(G_{xx},G_{xy})=(1,1).Comment: 10 pages, 5 figures, submitted to Phys. Rev. Let
Impact of electron injection on carrier transport and recombination in unintentionally doped GaN
RD50 Status Report 2008 - Radiation hard semiconductor devices for very high luminosity colliders
The objective of the CERN RD50 Collaboration is the development of radiation hard semiconductor detectors for very high luminosity colliders, particularly to face the requirements of a possible upgrade scenario of the LHC.This document reports the status of research and main results obtained after the sixth year of activity of the collaboration