Dimensionality tuning of strongly correlated van-der-Waals materials: a route to multifunctional quantum devices

Dimensionality is hugely important in low-temperature physics, the study of materials and the behaviour of electrons and other excitations in solid crystals. The underlying mathematics and the resulting observed behaviour of a material or system is hugely and fundamentally different and exotic if its character becomes two-dimensional rather than the familiar 3D. Even more fascinating and elusive is the fuzzy halfway ground of how a system behaves as it is pushed from one regime to the other - '2.5D'.

A nascent revolution in alternatives to silicon-based electronics is increasingly turning to the physics of 2D materials to design new devices to overcome the challenges of ever-increasing miniaturisation and an ever-mounting drive to become more energy efficient. 2D layered crystals have unique advantages in this regard, as they can be cleanly and easily thinned down to single layers of atoms (as with the famous example of graphene), then stacked together in nigh-unlimited complex configurations to combine their exotic properties.

To design and use these systems at an application level, it is essential that the underlying physics, and with it both the limitations and possibilities intrinsic to the materials are fundamentally understood and tested. Furthermore, this research can inform potential new avenues to explore and the synthesis of new designer materials to fulfil established criteria.

A large volume of recent work on low-dimensional physics has focused on thickness control, to tune towards the `true 2D' limit of the atomic monolayer. A complementary approach is to tune the interactions from 2D to 3D by applying hydrostatic pressure - an extremely clean and powerful tuning parameter in a van-der-Waals (vdW) material. These materials are formed of strongly-bonded flat planes of atoms, linked only by the extremely weak van-der-Waals chemical bond - akin to static electric attraction. Applying pressure to such a system overwhelmingly has the effect of pushing the crystal planes together, strengthening bonds between them and allowing ever-increasing crosstalk. This will often have profound effects on the conductivity and magnetism seen in the system, including the discovery of exotic new states of matter.

I will use extremes of low temperature, high pressure, magnetic and electric fields to search for new functional and multifunctional quantum materials and tune existing systems into novel states, focussing on fundamental properties of transport and of magnetic and charge order in 2D materials. I will focus on fundamental properties of transport and magnetism in low-dimensional van-der-Waals materials, and then to nanoscale devices built from stacking individual atomic layers of different 2D materials together.

Extreme-conditions tuning of these nanodevices is a completely new and exciting research direction that brings together two very different fields of research with essentially no overlap - my unique background across these two areas, and quantum computing, will allow me to build a new interdisciplinary programme to explore exciting new physics.

These devices additionally harbour great potential for new technologies as well as blue-skies science interest. I am partnering with industry, and academic collaborators in electrical engineering, chemistry and materials science, to explore pathways to practical applications of the new materials, behaviours and architectures to be discovered. Potential uses are in new times of electronics and memory such as spintronics or low-power transistors, flexible electronics and precision sensors. I will also look to harness the exotic 'topological' properties of new 2D materials to build fault-tolerant new qubits for quantum computing, drawing on my expertise and contacts in this field.