Coupling donor and quantum dot in silicon for applications in quantum information processing – CODAQ
Quantum physics, when applied to computing, is projected to lead to revolutionary enhancements in computational speed and power. However, to construct such a "quantum” computer, its building blocks, called qubits, have to be resistant to environmental disturbance; they need to hold the information encoded within them for long periods. One of the most promising ways to create such qubits consists in exploiting the spin degree of freedom of natural atoms implanted in silicon. In order to transfer coherent information between distant qubits, it has been proposed to create spin buses in silicon out of artificial atoms called “quantum dots”, controlled with electrostatic gates.
This project propose to investigate the coherent coupling between a single donor atom and a quantum dot in silicon nanodevices, the elementray block to realise the spin buses.
First, we will develop a new technique to determine the spin state of a single donor, relying on a spin-to-charge conversion induced by bound-exciton optical transitions. This method shows several advantages like its function temperature range, up to 4K, and low magnetic field. It has been successfully used on assembly but never on a single donor.
Then, once this method is up and working, we will exploit it to demonstrate a certain number of spin manipulation protocole. In particular, using identified devices that exhibit a strong coupling between a quantum dot and a single donor, we will investigate the coherent manipulation and transfer of spin information between them.
The experiment will comprise three steps. The manipulation of the spin information with microwave excitations that will be used to create superposition of states. Its transfer back and forth between the two objects, for which we will study two methods, either by electron shuttling or by exchange interaction. And lastly the reading of the spin information, which is at the centre of this project, using the as-developped spin-to-charge conversion.
Finally, extended architectures comprising few donors and quantum dots will be considered and a transfer of information over longer distances will be tested.
Monsieur Matias Urdampilleta (CNRS - INSTITUT NEEL)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
INEEL CNRS - INSTITUT NEEL
Help of the ANR 400,000 euros
Beginning and duration of the scientific project: May 2016 - 48 Months