Majorana modes in a triple-terminal Josephson junction with embedded parallel-coupled double quantum dots

• We study Josephson effect in one triple-terminal junction with parallel double quantum dots.
• The supercurrent has opportunities to oscillate in period 4pi by tuning structural parameters.
• By introducing the concept of spinful many-particle Majorana modes, Majorana operator is defined.
• We provide a simple but feasible proposal for realizing Majorana modes in a nonmagnetic system.

We investigate the Josephson effect in one triple-terminal junction with embedded parallel-coupled double quantum dots. It is found that the inter-superconductor supercurrent has opportunities to oscillate in period 4π4π, with the adjustment of the phase differences among the superconductors. What is notable is that such a result is robust and independent of fermion parities, intradot Coulomb strength, and the dot-superconductor coupling manner. By introducing the concept of spinful many-particle Majorana modes, we present the analytical definition of the Majorana operator via superposing electron and hole operators. It can be believed that this work provide a simple but feasible proposal for the realization of Majorana modes in a nonmagnetic system.