Nonlocal conductance in three-terminal hybrid Al/InSb nanowire devices*

Majorana zero-energy modes (MZMs) emerge at the edges of a one-dimensional topological segment. Signatures of these modes are correlated zero-bias peaks (ZBPs) in the local conductance that emerge simultaneously at both edges. The energy gap that separates them from the continuum - the bulk topological gap - can be identified in the nonlocal conductance, which is insensitive to local Andreev levels or transmission resonances. Thus, it is a vital tool to distinguish nontopological zero-energy modes and MZMs. Here, we have realized hybrid three-terminal devices based on InSb nanowires. The proximity-induced superconductivity is achieved via selective shadow-wall deposition of Al thin films. We demonstrate a hard induced gap using voltage-bias spectroscopy and study the appearance of zero-bias peaks in the local conductance. Harnessing the three-terminal geometry, we investigate the evolution of the nonlocal conductance in a magnetic field before the transition to the normal state.