Shot noise in NS junctions with a Weyl superconductor

Abstract

We demonstrate that current-current correlations (in particular the shot noise), can be used to study the intrinsic superconductivity in a slightly doped Weyl semimetal. The system studied is an N-WS tunneling junction where the left electrode is a normal metal while the right electrode is a Weyl superconductor (WS). The superconductivity supports surface state with crossed flat bands thereby impact the low-energy spectrum. This spectrum displays a modified density of states in the gap region that strongly affects transport characteristics of the N-WS junction. The Fano factor is calculated as a function of the applied bias and is shown to be dependent essentially on the orientation of the surface of WS relative to the tunneling direction. If this orientation supports the occurrence of low-energy state, then the shot noise power decreases with decreasing voltage, a property similar to that prevailing in a junction with Majorana bound state.

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