Research
We explore the properties of materials where quantum mechanics and strong interactions produce new states of matter
In a class of materials known as strongly correlated electron systems, the standard model of electrons in solids breaks down because strong electronic interactions are present. When strong enough, this interaction forces electrons, which in ordinary metals behave as delocalised waves, to localise and behave as particles. Those materials show a luxuriant array of fascinating new states of matter in which magnetic, charge, orbital and structural orders compete for the ground state. In addition to being one of the most complex and greatest intellectual challenges of modern science, some of those materials also have great technological potential : cuprate superconductors and high thermoelectric power materials provide new technological solutions to growing problems of energy storage, transportation and production.
An emblematic example of quantum material are the high-Tc cuprate superconductors. Those materials have the highest known superconducting critical temperature at ambient pressure. Their phase diagram features several baffling mysteries. The basic questions we are trying to answer are: what is the organizing principle of the phase diagram of high-Tc cuprates? what is the mechanism for high-Tc superconductivity? We use high magnetic fields to suppress superconductivity in order to reach and determine the nature of the electronic interactions at play in the phase diagram and in the pairing mechanism of those systems.
We also study the triplet-superconductor candidate UTe2. It is a heavy fermion superconductor, exhibiting unconventional superconductivity that challenges traditional theories. UTe2 has reavealed several intriguing features such as magnetic field-reinforced and magnetic field induced superconductivity.
Our work also focuses on the properties of quantum spin liquids. Quantum spin liquids are long-sought exotic states of matter characterized by an absence of magnetic order or spin freezing down to T=0, macroscopic entanglement, and emergent fractionalized excitations. The current best prospect to achieve a quantum spin liquid in two-dimensions is the spin-1/2 nearest-neighbour Heisenberg antiferromagnet on the Kagome lattice model. We study different material realisation of this model and its variations.
