Archer Materials Limited, a semiconductor company advancing the quantum technology and medical diagnostics industries, has improved the electron spin lifetime of its novel manufacturable quantum carbon film (see ASX announcement on 30 September 2024) to 800 ns (nanosecond), up from 385 ns, and the films’ reproducibility from sample-to-sample.
The improved electron spin lifetimes and the sample-to sample repeatability is an important development achieved by Archer, as it moves closer to realising devices like qubits and magnetic sensors. Archer will now look to reproduce and translate these results from the manufacturable carbon film base to silicon or quartz chips and then ensure the repeatability of the results between sample chips.
Spin lifetimes of 800 ns have been demonstrated under certain synthesis conditions, although some work is required to reproduce this on silicon (or other) substrates for chips. Uniformity across a wafer (ensuring consistent electrical and optical properties) and repeatability between sample chips (variability) is critical for reproducing the chips. Both uniformity and variability have been improved significantly, with standard deviations of 25-100% down to ~7%.
Realisation of quantum devices like qubits or quantum magnetic sensors requires demonstration of key quantum effects like Coulomb blockade (see announcement on 30 October 2024) and electrically detected magnetic resonance (“EDMR”). Some of these effects have been recently demonstrated and work continues at Queen Mary University of London (“QMUL”) and The École Polytechnique Fédérale de Lausanne (“EPFL”).
It is equally important to increase the spin lifetime and film reproducibility. For example, increasing towards 1 microsecond at room-temperature allows better functionality for the control and readout (the reading of the output of quantum information) qubits on the device.
In other technology, like quantum magnetometers, these lifetimes entitle sensitivities to incredibly small magnetic fields of nanotesla to microtesla ranges. To scale from single qubits or magnetic sensor pixels, the uniformity across a chip and from run-to-run is also critical.
The spin lifetimes have been verified on nanoislands of the films, showing no significant change of electron spin lifetime when patterning from bulk films to nanoscale dots, down to a size of 150 nanometers.
Commenting on the carbon film development, Greg English, Executive Chair of Archer, said, “These advancements of Archer’s manufacturable quantum carbon film material bring the 12CQ project closer to the readout of qubits and quantum magnetic sensing. Readout is an important component for the development of our quantum computing chip and bolstering magnetic sensing will go towards the work being done on our tunnel magnetoresistance sensors.
“The team is now working with its partners to research how its carbon films and carbon nano onions can get further towards a qubit, and the sensing and reading of quantum information at room temperature, to ultimately bring quantum computing and sensing to life in everyday environments.”
The Board of Archer authorised this announcement to be given to ASX.
