Quantum coherent spin physics in condensed matter

This studentship will explore experimentally a range of condensed matter quantum spin systems exhibiting potential for applications in quantum technologies. To this end, it will develop and deploy a range of innovations in magnetic resonance methods.

Condensed matter quantum spins can be deployed as the active elements of quantum sensors of magnetic fields. Various time-resolved magnetic resonance protocols have been proposed (for example, using multi-pulse sequences or spin locking techniques) to engineer the parameters of the sensor (for example the frequency to which it is sensitive and the bandwidth).

The project will explore the use of the highly coherent electronic quantum spin in N@C60 as the working element of a magnetic field sensor, and establish the operating parameters and limits of performance.

Traditionally, magnetic fields are used to control quantum spins via the Zeeman interaction. However, there would be significant architectural advantages for quantum technologies if spin qubits could be controlled using electric fields, because it is possible to localise and control electric fields on shorter length scales than magnetic fields. This project will continue the recent advances from the research group to elucidate the mechanisms for couplings between electric fields and spins in molecules.

The project will identify the sensitivity of molecular spin Hamiltonians to externally applied d.c. electric fields. Based on the insights acquired from this, microwave resonators will be designed such that the sample can be subjected to an oscillatory electric field resonant with spin transitions. These will be used to drive coherent molecular spin operations electrically rather than magnetically.

The development of technologically useful quantum devices based on molecular spins will be accelerated by combining spin excitations with other degrees of freedom, such as, for example, electrical conductivity and optical properties. In developing this capability, it will be important to be able to conduct traditional ESR experiments on structures, such as thin films, that are compatible with device geometries.

This will require progress in instrumentation to improve signal-to-noise in low-sensitivity samples, including implementation of cryogenic amplification of microwave signals.

This project falls within the EPSRC research areas: "Condensed matter: magnetism and magnetic materials"; "Optoelectronic devices and circuits"; "Quantum devices, components and systems"; "Radio frequency and microwave devices"; and "Spintronics". It is supported in part by a graduate scholarship from Magdalen College, Oxford.