Attaching Thiolated Superconductor Grains on Gold Surfaces for Nanoelectronics Applications

We report that the high critical temperature superconductor (HTCS) LaCaBaCu 3 O 7 in the form of nanograins can be linked to Au(111) surfaces through self assembled monolayers (SAMs) of HS--C 8 H 16 --HS [octane (di)thiol]. We show that La1113 particles (100 nm mean diameter) can be functionalized by octane (di)thiol without affecting their superconducting critical temperature ($T_{\text{C}}=80$ K). X-ray photoemission spectroscopy (XPS) analysis reveals that the thiol functional heads link the superconducting grain surfaces creating sulfonates and we deduce that bonding between the S atoms and Cu(1) atoms of the La1113 structure would be formed. We suggest a design for a superconducting transistor fabricated by immobilized La1113 nanograins in between two gold electrodes which could be controlled by an external magnetic field gate.