Magnetic-field driven evolution of zero-energy mode on Bi islands deposited on Fe(Te,Se)

TL;DR

This study explores how magnetic fields influence zero-energy modes on Bi islands on Fe(Te,Se), revealing non-monotonic behavior linked to topological edge states and providing insights into Majorana zero modes.

Contribution

It demonstrates the magnetic-field-dependent evolution of zero-bias conductance peaks on Bi islands, highlighting their connection to topological edge states and Majorana modes.

Findings

ZBCPs observed across Bi islands consistent with Majorana signatures

ZBCPs show non-monotonic evolution with magnetic field strength

Magnetic-field-enhanced topological edge states influence ZBCP behavior

Abstract

We investigate the magnetic-field dependent evolution of the zero-bias conductance peaks (ZBCPs) on the nanoscale bismuth islands grown on the FeTe$_{0.55}$Se$_{0.45}$ substrate. The ZBCPs can be observed throughout the entire region on these islands, and their characteristics align with the signatures of Majorana zero modes. Remarkably, the evolution of ZBCPs on these islands exhibits anomalous behavior under varying magnetic fields: The magnitude of ZBCPs is first enhanced at weak fields lower than 2 T and then suppressed as the fields further increase. We attribute the non-monotonic evolution of the ZBCPs to the magnetic-field-enhanced topological edge states on these Bi islands. Our findings provide valuable insights into the probable origin of the Majorana zero modes in the Bi-island platform and the magnetic-field response of topological edge states.