On-Surface Atomic Spins with Outstanding Quantum Coherence

The quantum nature of a physical system often emerges from its fundamental building blocks and demands a profound understanding to harvest its advantages for quantum devices.

Their design requires knowledge about the atomic-scale environment of a quantum object to protect it from noise and energy exchange.

For that purpose, spins on surfaces studied and controlled by a combination of scanning tunnelling microscopy (STM) and electron spin resonance (ESR) has emerged as an atomic workbench that permits to resolve quantum systems such as single atoms and molecules.

However, up to now the coherent properties, in particular the phase coherence time, remain much worse than in other quantum architectures such as nitrogen-vacancy centres in diamond or superconducting qubits. In ATOMQUANT, I aim to improve the coherent properties of spins on surfaces by several orders of magnitude.

The main goal is to create a new atomic-force microscopy (AFM)-based architecture for quantum information processing and magnetic sensing operating on the atomic scale.

I aim to achieve this goal i) by improvements in instrumentation: Here, I will set up single spin resonance in a milliKelvin-AFM setup, based on the technique of magnetic exchange force microscopy. ii) by addressing remote substrate nuclear spins and by utilizing them as a highly coherent quantum resource.

This will here be realized by 25Mg nuclear spins that are found in the commonly used magnesium oxide substrate iii) by overcoming major challenges for the detection of spins on surfaces such as requirements for low temperatures and hurdles for device integration.The results of ATOMQUANT will have the potential to bring quantum research to the atomic limit, allowing for exploration of potential qubit systems with outstanding quantum properties in-situ and atom-by-atom.

My previous extensive experience in the field of ESR-STM provides the best possible conditions to conduct this innovative high potential research endeavour.