Initialisation and measurement of semiconductor spin qubits in the high-temperature/low magnetic field limit

State preparation and measurement of single-electron spin qubits typically relies on spin-to-charge conversion where a spin dependent charge transition of the electron is detected by a coupled charge sensor [1, 2]. Typically, this process requires that the qubit energy be much larger than the temperature of the system [3]. Here, we demonstrate an initialisation and measurement technique that is resilient to charge noise and high-temperature qubit operation. Using a new measurement procedure, we show readout fidelities above 90% for qubit energies just 3 times larger than the thermal energy. The initialisation procedure allows for single-electron spin state preparation with a fidelity of 99% within 20ms. Finally, the readout technique opens up a new regime of high-temperature/low magnetic field single-spin physics.

 

[1] Keith, D. et al. Phys. Rev. X 9, 041003 (2019)

[2] Elzerman, J. M. et al. Nature 430, 431-435 (2004)

[3] Keith, D. et al. New J. Phys. 21, 063011 (2019)