The Influence of Coulomb Interaction on the Efficiency of Quantum Dot Josephson Diode with a Magnetic Impurity

We investigate the impact of electronic correlation effects on diode efficiency in a quantum dot Josephson junction that contains a single magnetic impurity. This study employs the exact diagonalization method within the framework of the zero bandwidth approximation. By adjusting system parameters such as the coupling strength between the quantum dot and the impurity, the intra‐dot Coulomb interaction strength, we examine how these factors affect the Josephson current, spin correlation functions, and the efficiency of Josephson diodes. We find that various electronic correlation effects exist in the system. When the system parameters change, these electronic correlation effects can exhibit phenomena of both competition and cooperation. This not only leads to the emergence of – Josephson phase transitions but also alters both the magnitude and sign of the diode efficiency in the system. Our research findings indicate that these intriguing physical mechanisms profoundly influence properties such as current magnitude and efficiency in Josephson diodes.