Identifying Majorana and accidental zero modes in altermagnet heterostructures via transport studies in both static and driven scenarios

We theoretically investigate differential conductance, shot
noise, and Josephson current signatures of topological and non-topological
zero modes in a one-dimensional Rashba nanowire proximitized to an s-wave
superconductor and a d-wave altermagnet (AM), which is advantageous to
retain the proximity induced superconducting gap compared to the external
magnetic field. In the static regime, the system hosts both Majorana zero
modes (MZMs), characterized by a nontrivial winding number, and non
topological accidental zero modes (AZMs) with vanishing winding number.
Implementing a three-terminal setup, we demonstrate that MZMs exhibit
quantized zero-bias conductance (ZBC), while AZMs yield non-universal ZBC,
enabling a clear distinction between them. Furthermore, upon periodic
driving, AZMs can be gapped out or converted into π-Floquet Majorana end
modes (FMEMs), referred to as topological AZMs (TAZMs). These FMEMs are
characterized by dynamical winding numbers and exhibit 4π-periodic
Josephson response, in contrast to trivial AZMs which retain conventional
2π periodicity. Our work establishes a comprehensive framework to realize,
identify, and differentiate between topological and non-topological modes
in both static and dynamic scenarios based on AM hybrid structures.