Distort-to-Grasp · Distorting unconventional superconductivity - A grasp of electronic phases with multiple broken symmetries

When electrons in a solid interact strongly, they can form novel states of matter with fascinating technological possibilities and intriguing intellectual challenges. They might realize the macroscopic quantum state with dissipationless transport – superconductivity – or spontaneously lose spherical symmetry – an electronic nematic state. Surprisingly, more and more nematic superconductors, combining both, have recently been discovered. Such observations suggest a fundamental link between nematicity and superconductivity that is not yet understood. Progress is hindered by an acute lack of systematic data on the nematicity-superconductivity interaction, due to the absence of routine high-resolution probes of nematicity that are applicable in the superconducting state. Accurately determining lattice distortions and elastic moduli would be suitable, but the corresponding classic techniques are not possible or practical for many novel materials.To relieve this scarcity of knowledge, I propose to establish a novel “distortiometry” approach based on measuring a material’s elastic response to anisotropic stress. Taking full advantage of established capacitance dilatometry and recent advances in strain-tuning techniques, the approach will be at the center of a specialized program based on distortions to get a grasp of nematic superconductivity. Having confirmed the new method’s versatility, resolution and reliability, I will study several platform materials where nematicity and superconductivity interact in the context of quantum criticality, investigate novel topological materials whose superconductivity appears to be nematic itself, and explore new nematic superconductors. Thus, I will gain new insights into mechanisms of unconventional superconductivity and its multiple degrees of freedom. My new widely applicable techniques will be a powerful addition to the arsenal of experimental solid state physics and material science.