Piezoelectric-based uniaxial strain cell with high strain throughput and homogeneity

Abstract

We seek for novel electronic phenomena by using external strain engineering, namely, by the application of external uniaxial strain. A piezoelectric-based uniaxial strain cell has been recently developed by Hicks et al. and successfully utilized for studies of various unconventional superconductors. Here, we propose a modified design that minimizes effects originating from the asymmetry of the strain cell design, in particular with minimal bending moments, by placing the sample at the axis of mirror symmetry of the device to balance out the reactive forces. Results of finite element analyses indicate that placing the sample offset to the axis of the mirror symmetry indeed causes an increase of strain inhomogeneity up to 10%, both at room temperature and at 4.2 K. Furthermore, we found that this bending reduces the overall achievable strain down to 30% of its maximal value without the bending. We also experimentally demonstrate the potential of our constructed device by tracking the displacement of the anvils of the strain cell with a parallel plate capacitor. The full range of motion of the piezo-stacks were demonstrated at room temperature. With a sample and at 0.9 K, we achieved a uniaxial strain of −1.5%, which is enough to induce electronic change in typical materials.