Prof. Andy Mackenzie

Max Planck Institute of Solids, Dresden and University of St. Andrews, Scotland

In this talk I will discuss rapid developments, taking place over the past decade or so, in applying uniaxial pressure to quantum materials using piezo-activated vices. In the first stages of using the new experimental capabilities, the focus was on applying large static uniaxial pressures, up to 3 GPa so far, to generate large changes in the physical properties of unconventional superconductors and magnets. The vice provided the tuning of the properties, which were probed by other techniques such as electrical resistivity or magnetic susceptibility. Only more recently has it become clear that exquisitely precise thermodynamic information can be obtained from simultaneously probing the elastic response of the materials to the applied pressure. These new techniques rely on combining static pressure with a tiny oscillatory component, and locking in to the responses of the material at the frequency of those oscillations. They are enabled only via the basic strategy of applying the pressure using piezoelectric actuators. In my opinion an entirely new avenue of quantum materials research can be opened with this new combination of tuning and measurement, as I will attempt to explain.