Enhanced coherence of all-nitride superconducting qubits epitaxially grown on silicon substrate

Abstract

Long coherence times are a key property of superconducting qubits, but in conventional Al-based Josephson junctions they are limited by microscopic two-level systems. Here, NbN-based qubits on Si promise to overcome this limitation, showing an energy relaxation time T1 = 16.3 μs and a spin-echo dephasing time T2 = 21.5 μs.