lattice dynamics in P-doped BaNi2As2

Signatures of nematic fluctuations have now been observed in various families of superconductors (SC) and have triggered intense investigations on the role of nematicity in the pairing mechanism. Recently, superconducting BaNi2(As,P)2 has received significant attention as a candidate system for charge-driven electronic nematicity. In this tetragonal system, a unidirectional charge density wave (CDW) order sets in before a structural transition to a triclinic phase occurs. We have recently performed a combined diffuse scattering (DS) and inelastic x-ray scattering (IXS) study in BaNi2(As,P)2, in which we have identified the soft phonon responsible for the formation of the IC-CDW. Here we propose to complete our study by extending our measurements to higher P-doping levels, for which the triclinic transition is fully supressed, and the superconducting Tc is strongly increased.