# Tests of nematic-mediated superconductivity applied to Ba$_{1-x}$Sr$_x$Ni$_2$As$_2$

## TL;DR

This paper proposes empirical tests, supported by calculations, to investigate whether nematic quantum fluctuations mediate superconductivity in Ba$_{1-x}$Sr$_x$Ni$_2$As$_2$, emphasizing uniaxial strain experiments as a key probe.

## Contribution

It introduces specific experimental tests and theoretical calculations to assess nematic-mediated pairing in a tunable superconductor system.

## Key findings

- Predictions for uniaxial strain experiments to detect nematic fluctuations
- Quantitative model supporting nematicity's role in pairing
- Potential evidence for nematic-mediated superconductivity

## Abstract

In many unconventional superconductors, nematic quantum fluctuations are strongest where the critical temperature is highest, inviting the conjecture that nematicity plays an important role in the pairing mechanism. Recently, Ba$_{1-x}$Sr$_x$Ni$_2$As$_2$ has been identified as a tunable nematic system that provides an ideal testing ground for this proposition. We therefore propose several sharp empirical tests, supported by quantitative calculations in a simple model of Ba$_{1-x}$Sr$_x$Ni$_2$As$_2$. The most stringent predictions concern experiments under uniaxial strain, which has recently emerged as a powerful tuning parameter in the study of correlated materials. Since uniaxial strain so precisely targets nematic fluctuations, such experiments may provide compelling evidence for nematic-mediated pairing, analogous to the isotope effect in conventional superconductors.