Current Phase-relation of an Unconventional Josephson Junction

The Josephson effect lies in the basis of superconductivity and plays a significant role in many applications of modern day technology, ranging from ultra-sensitive magnetic flux sensors, through complex signal processing circuits to quantum bits. A key element of the dc Josephson effect is the dependence of the supercurrent I_s on the phase difference across the Josephson junction. The study of this current-phase relation (CPR) may provide important information about a junction’s parameters and characteristics. Chiral molecules have been shown to act as highly efficient spin selective filters and induce magnetization and triplet-pairing superconductivity. We used a three-terminal, three- junction SQUID (mSQUID) which allows a direct measurement of the CPR to examine the effect of chiral molecules attached to a Josephson junction. Although we did not find significant period changing of the CPR or major phase shifts, our data did show an increase of the critical current and an interesting small phase shift of the interference pattern before and after the adsorption of chiral molecules on the mSQUID.