Supercurrent and Conductance Quantization in a Superconducting Quantum Point Contact

We study the quantization of the supercurrent and conductance of a superconducting quantum point contact (SQPC) in a superconductor-two dimensional electrongas-superconductor (S-2DEG-S) Josephson junction with a split gate. The supercurrent and the conductance values change stepwise as a function of the gate voltage. We observe the onset of the first transport mode contributing both to the supercurrent and the conductance of the SQPC. Furthermore the steps in the supercurrent and the conductance appear at the same gate voltage values. This shows, that each transport mode in the SQPC contributes both to the normal state conductance and to the supercurrent.