Probing robust Majorana signatures by crossed Andreev reflection with a quantum dot

We propose a three-terminal structure to probe robust signatures of Majorana\nzero modes. This structure consists of a quantum dot coupled to the normal\nmetal, s-wave superconducting and Majorana Y-junction leads. The zero-bias\ndifferential conductance at zero temperature of the normal-metal lead peaks at\n$2e^{2}/h$, which will be deflected after Majorana braiding. This quantized\nconductance can entirely arise from the Majorana-induced crossed Andreev\nreflection, protected by the energy gap of the superconducting lead. We find\nthat the effect of thermal broadening is significantly suppressed when the dot\nis on resonance. In the case that the energy level of the quantum dot is much\nlarger than the superconducting gap, tunneling processes are dominated by\nMajorana-induced crossed Andreev reflection. Particularly, a novel kind of\ncrossed Andreev reflection equivalent to the splitting of charge quanta $3e$\noccurs after Majorana braiding.\n