Fig. 5: Phase diagram for \({{{{{\rm{Ba}}}}}}{{{{{{\rm{Ni}}}}}}}_{2}{({{{{{{\rm{As}}}}}}}_{1-x}{{{{{{\rm{P}}}}}}}_{x})}_{2}\).
The transition temperatures for the triclinic phases are determined from transport and thermal expansion measurements. We also report the temperature Tρ of the minimum in dR/dT which corresponds to an orthorhombic transition in the parent compound (Supplementary Note 2). The superconducting transition temperature is measured by specific heat (Supplementary Note 2). The onset of the C-CDW seen with XRD coincides with the triclinic transition, whereas the intensity of the I-CDW satellites increases strongly at TI-CDW, just above Tρ (see Fig. 2). The onset of the broadening of the Eg,1 Raman phonons is indicated by T* (see also Supplementary Note 3). Horizontal error bars correspond to the uncertainty on the P-concentration as determined from EDX (Supplementary Note 1). Vertical error bars reflect the accuracy with which the various temperatures can be determined from Fig. 2.
