Differential current noise as an identifier of Andreev bound states that induce nearly quantized conductance plateaus

Abstract

Quantized conductance plateaus, a celebrated hallmark of Majorana bound states (MBSs) predicted a decade ago, have recently been observed with small deviations in iron-based superconductors and hybrid nanowires. Here, we demonstrate that nearly quantized conductance plateaus can also arise from trivial Andreev bound states (ABSs). To avoid ABS interruptions, we propose identifying ABS-induced quantized conductance plateaus by measuring the associated differential current noise P versus bias voltage V. Specifically, for a quantized conductance plateau induced by one or multiple low-energy ABSs, the associated P(V) curve exhibits a double-peak around zero bias, with the peak positions at e|V|≈3kBT (where T is the temperature) and peak values larger than 2e3/h. These features greatly contrast those of an MBS or quasi-MBS, whose P(V) curve displays a broad zero-bias dip and is consistently below 2e3/h. This protocol can be practically implemented in a variety of MBS candidate platforms using an electrode or STM tip as a probe.

Source-reported materials — not catalogue approval

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