Majorana field-effect transistor realization in hybrid quantum dot–zigzag nanowire devices

We theoretically investigate quantum transport in a T-shaped nanodevice consisting of a quantum dot side-coupled to a finite zigzag chain deposited on a proximitized superconducting substrate. Using the non-equilibrium Green’s function formalism within the Keldysh framework, we show that Majorana bound states generate a robust parity-independent zero-bias conductance signature that remains preserved for chain lengths ranging from ( n = 3) to ( n = 8). The current–voltage characteristics exhibit multiple finite-bias plateaus and distinct transport regimes arising from the interplay between Majorana-induced and conventional fermionic states. By tuning the quantum dot–chain coupling, superconducting pairing amplitude, and electrode hybridization strength, the transport response can be effectively modulated, establishing the operational framework of a Majorana field-effect transistor. These findings clarify the role of finite-size effects and quantum interference in topological hybrid systems and are relevant to emerging semiconductor–superconductor and optical lattice platforms for Majorana physics. These results demonstrate the robustness of Majorana signatures in finite zigzag chains and highlight the potential of this architecture for the implementation of Majorana field-effect transistor devices.