Epitaxial Growth of Rhenium with Sputtering

Epitaxial superconducting films of refractory metals are a promising new template for single crystal tunnel barriers in Josephson junction quantum bit (qubit) devices. In existing Josephson junction qubits, it is believed that the widely-used amorphous AlOx tunnel barriers have undesirable two-state fluctuators. It is speculated that single-crystal tunnel barriers such as sapphire (α-Al2O3) may be free of such decoherence sources.