Muon Spin Relaxation studies on superconducting Ba1-xSrxNi2As2

The interplay between nematicity, magnetism and superconductivity is the key to understand the physics of iron-based superconductivity. Recently, BaNi2As2 and SrNi2As2, both being superconducting below 0.6 K without evidence of magnetic order or fluctuations, offers a unique opportunity to study the role of nematic fluctuations in the electron Cooper pairing without the effect of magnetic fluctuations. To elucidate the precise relationship between nematicity and superconductivity in Ba1-xSrxNi2As2, we propose to perform μSR experiments to measure the magnetic penetration depth of Ba1-xSrxNi2As2 (x = 0, 0.7, and 1). The success of the experiments will tell us the doping evolution the superconducting gap symmetry, which should help to understand how nematic fluctuations enhance superconductivity in Ba1-xSrxNi2As2.