Minute-long spin coherence from diode control of magnetic noise

Embedding solid state spin defects into classical semiconductor devices can enable new opportunities for quantum information processing. By tuning the bias of a highly purified silicon carbide p–i–n diode into depletion, we remove both electrical and magnetic noise and observe unprecedented electron-spin coherence. Nuclear spins controlled by the electron also show longer relaxation and diode-enhanced coherence, with Hahn-echo times reaching minutes. This result demonstrates that materials control in tandem with device integration can produce ultra-coherent solid-state quantum nodes and processors.