Absence of Precursor Incommensurate Charge Order in Electronic Nematic Ba0.35Sr0.65Ni2As2

Recent discoveries of charge order and electronic nematic order in the iron-based superconductors and cuprates have pointed towards the possibility of nematic and charge fluctuations playing a role in the enhancement of superconductivity. The Ba1-xSrxNi2As2 system, closely related in structure to the BaFe2As2 system, has recently been shown to exhibit both types of ordering without the presence of any magnetic order. We report single-crystal x-ray diffraction experiments on Ba0.35Sr0.65Ni2As2, providing evidence that the previously reported incommensurate charge order with wave-vector (0, 0.28, 0)(tet )in the tetragonal state of BaNi2As2 vanishes by 65% Sr substitution together with nematic order. Our measurements suggest that the nematic and incommensurate charge orders are closely tied in the tetragonal state and show that the (0, 0.33, 0)(tri )charge ordering in the triclinic phase of BaNi2As2 evolves to become (0, 0.5, 0)(tri) charge ordering at x = 0.65 before vanishing at x = 0.71.