ABSTRACT
Ballistic electron transport is a key requirement for existence of a topological phase transition in proximitized InSb nanowires. However, measurements of quantized conductance as direct evidence of ballistic transport have so far been obscured due to the increased chance of backscattering in one-dimensional nanowires. We show that by improving the nanowire-metal interface as well as the dielectric environment we can consistently achieve conductance quantization at zero magnetic field. Additionally we study the contribution of orbital effects to the sub-band dispersion for different orientation of the magnetic field, observing a near-degeneracy between the second and third sub-bands.
ABSTRACT
Signatures of Majorana fermions have recently been reported from measurements on hybrid superconductor-semiconductor nanowire devices. Majorana fermions are predicted to obey special quantum statistics, known as non-Abelian statistics. To probe this requires an exchange operation, in which two Majorana fermions are moved around one another, which requires at least a simple network of nanowires. Here, we report on the synthesis and electrical characterization of crosses of InSb nanowires. The InSb wires grow horizontally on flexible vertical stems, allowing nearby wires to meet and merge. In this way, near-planar single-crystalline nanocrosses are created, which can be measured by four electrical contacts. Our transport measurements show that the favourable properties of the InSb nanowire devices-high carrier mobility and the ability to induce superconductivity--are preserved in the cross devices. Our nanocrosses thus represent a promising system for the exchange of Majorana fermions.
