Extra Seminar - Würzburg ToCoTronics Colloquium

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.