A Majorana smoking gun for the superconductor-semiconductor hybrid topological system

TL;DR

This paper proposes that observing oscillatory splitting of zero bias conductance peaks under specific conditions can definitively confirm the presence of Majorana modes in superconductor-semiconductor nanowire systems.

Contribution

It provides a theoretical framework predicting how zero bias peak splitting behavior can serve as a conclusive signature of Majorana modes, clarifying experimental conditions.

Findings

Splitting oscillations depend on Zeeman field and chemical potential.

Suppression of oscillations occurs when density is constant.

Conditions for unambiguous Majorana detection are identified.

Abstract

Recent observations of a zero bias conductance peak in tunneling transport measurements in superconductor--semiconductor nanowire devices provide evidence for the predicted zero--energy Majorana modes, but not the conclusive proof for their existence. We establish that direct observation of a splitting of the zero bias conductance peak can serve as the smoking gun evidence for the existence of the Majorana mode. We show that the splitting has an oscillatory dependence on the Zeeman field (chemical potential) at fixed chemical potential (Zeeman field). By contrast, when the density is constant rather than the chemical potential -- the likely situation in the current experimental set-ups -- the splitting oscillations are generically suppressed. Our theory predicts the conditions under which the splitting oscillations can serve as the smoking gun for the experimental confirmation of the elusive Majorana mode.