arXiv subjects

G. Bastian

Publications and source records attributed to G. Bastian.

3 recordsLinked to original sources

arXiv2000

Enhanced quantized current driven by surface acoustic waves

We present the experimental realization of different approaches to increase the amount of quantized current which is driven by surface acoustic waves through split gate structures in a two dimensional electron gas. Samples with driving frequencies of up to 4.7 GHz have been fabricated without a deterioration of the precision of the current steps, and a parallelization of two channels with correspondingly doubled current values have been achieved. We discuss theoretical and technological limitations of these approaches for metrological applications as well as for quantum logics.

cond-mat.mes-hall↗

arXiv2000

Comment on "Critical currents in ballistic two-dimensional InAs-based superconducting weak links"

In ballistic Josephson junctions the experimentally observed iv-characteristics deviate from the theoretically predicted behaviour. Recently, Heida et al. Phys. Rev. B 60, 13135 (1999) discussed this problem and offered an explanation for the discrepancy. Considering this explanation, several contradictions to the authors' data as well as to other publications are shown.

cond-mat.mes-hall↗

arXiv2000

Ballistic reflection at a side-gate in a superconductor-semiconductor-superconductor structure

We have fabricated a sub-micron-sized structure consisting of an InAs-based 2DEG, two narrow Nb leads and a gate, where the indirect ballistic transport between the non-oppositely superconducting contacts can be controlled by the voltage applied to the gate. This new kind of tuneable junction can be used for applications and allows several fundamental questions related to the transport mechanism to be studied. First results of experiments carried out in this respect are presented.

cond-mat.mes-hall↗