arXiv subjects

A. Vogl

Publications and source records attributed to A. Vogl.

3 recordsLinked to original sources

arXiv2010

Fractional quantum Hall effect in CdTe

The fractional quantum Hall (FQH) effect is reported in a high mobility CdTe quantum well at mK temperatures. Fully-developed FQH states are observed at filling factor 4/3 and 5/3 and are found to be both spin-polarized ground state for which the lowest energy excitation is not a spin-flip. This can be accounted for by the relatively high intrinsic Zeeman energy in this single valley 2D electron gas. FQH minima are also observed in the first excited (N=1) Landau level at filling factor 7/3 and 8/3 for intermediate temperatures.

cond-mat.mes-hall↗

arXiv2009

All electrical measurement of the density of states in (Ga,Mn)As

We report on electrical measurements of the effective density of states in the ferromagnetic semiconductor material (Ga,Mn)As. By analyzing the conductivity correction due to enhanced electron-electron interaction the electrical diffusion constant was extracted for (Ga,Mn)As samples of different dimensionality. Using the Einstein relation allows to deduce the effective density of states of (Ga,Mn)As at the Fermi energy.

cond-mat.mes-hall↗

arXiv2008

Quantum transport in ferromagnetic Permalloy nanostructures

We studied phase coherent phenomena in mesoscopic Permalloy samples by exploring low temperature transport. Both, differential conductance as a function of bias voltage and magnetoconductance of individual wires display conductance fluctuations. Analysis of these fluctuations yields a phase coherence length of $\sim250$ nm at 25 mK as well as a $1/\sqrt{T}$ temperature dependence. To suppress conductance fluctuations by ensemble averaging we investigated low temperature transport in wire arrays and extended Permalloy films. In these samples we have measured conductance corrections which stem from electron-electron interaction (EEI) but attempts to detect signatures of weak localization were without success.

cond-mat.mes-hall↗