Gabriel Perko-Engel L&S Sciences
Measuring Nematically Ordered Superconductivity with Resonant Ultrasound Spectroscopy
Most iron, and much nickel-based superconductivity is found in the same region as a magnetically ordered state. The transition temperatures for these magnetic states have in turn been found to be strongly correlated with those of “nematic” phase transitions reducing the lattice symmetry from tetragonal to orthorhombic. Given the intersection between these nematically fluctuating regions and superconducting phases in so many unconventional superconductors, several questions naturally arise. This first of these is of course what connection exists between the nematic phase and superconductivity. But, beyond that, the origin of the nematic phase itself isn’t completely clear in and of itself. And the existence of the aforementioned magnetic phase creates a confounding variable, making it challenging to disentangle nematic from magnetic order in the effects on superconductivity. BaNi2As2 is a nematically ordered superconductor with no observed long-range magnetic order. Using resonant ultrasound spectroscopy (RUS), I hope to extract complete symmetry information for BaNi2As2 in the region of its nematic phase and shed some light on these mysteries.