Extended coherence of electron and nuclear spins in epitaxial purified silicon devices fabricated by atomic lithography.*

The nuclear spin free environment in isotopically pure silicon dramatically supresses magnetic noise, giving rise to unprecedented coherence times of spin qubits [1]. Likewise, the single crystal environment provided by epitaxial growth exhibits extremely low level of charge noise, crucial for high performance of electrically controlled operations of a qubit in a nanoelectronic device [2]. We have recently realised precision donor qubits in isotopically pure crystalline silicon-28 and present our results to benchmark against charge and magnetic noise measurements in natural silicon, highlighting that they achieve the necessary coherence properties for quantum information processing.

[1] J. T. Muhonen et.al, Storing quantum information for 30 seconds in a nanoelectronic device, Nature Nanotechnology 9, 986–991 (2014).

[2] L. Kranz et al. Exploiting a Single-Crystal Environment to Minimize the Charge Noise on Qubits in Silicon, Advanced Materials 32 (40) 2003361 (2020)