Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Professor Elena Gati, Institute of Physics, Goethe University, 60438 Frankfurt Main, Germany, and Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany
Professor Amalia Coldea
Abstract
Quantum magnets host a wide range of collective states that emerge from the interplay of strong correlations, competing interactions, and topology. Identifying and distinguishing these states experimentally requires tuning parameters that can be applied in a precise, controlled and reversible manner.
Uniaxial pressure and strain are particularly promising tuning parameters for quantum magnets, as they directly modify lattice symmetries and frustrated interactions. However, only recent technical developments have made it possible to apply strain in a controlled way at low temperatures. These advances now enable systematic experimental studies of the phase diagrams of frustrated and other exotic quantum magnets.
In this talk, I will outline the concept of strain and the experimental tools used to apply it, and then focus on frustrated Mott insulators, for which uniaxial pressure offers a particularly effective way to tune the frustration. Using a triangular-lattice magnet as an example [1], I will show that the levels of strain achievable in current experiments are sufficient to significantly influence frustration in real materials. These experimentally derived phase diagrams provide an important, new benchmark for comparison with theoretical models.
Time permitting, I will also touch on how applying symmetry-breaking strains in a controlled manner plays a crucial role in probing and tuning unconventional multipolar orders [2], such as altermagnetism.
[1] Lieberich, …, EG, Science Advances 11, eadz0669 (2025).
[2] Ohlendorf, …, EG, to be submitted.