Orbital structure of charge density waves in BaNi$_2$(As$_{1-x}$P$_x$)$_2$ [dataset]

BaNi$_2$As$_2$ can be seen as the non-magnetic analogue of the prototype material of the Fe-based superconductors BaFe$_2$As$_2$. At ambient conditions both materials share the same tetragonal I4/mmm structure. At lower temperatures (T≈150K) an incommensurate charge density wave (I-CDW) was found. The I-CDW survives a distortion towards an orthorhombic phase (T=142K) before it is replaced by a commensurate CDW below a triclinic transition (T=137K). Below T$_c$=0.7K the material gets superconducting. The different orders and structural phases can be tuned by substitution e.g. by Sr, Co or P. Recent investigations of the Sr-substituted system give evidence of electronic nematic fluctuations and propose the system as electronic tunable nematic system. The interplay of the different orders in BaNi$_2$As$_2$ and orbital
structure of the charge density waves remain unclear. We propose to investigate the orbital structure of the CDWs by a detailed REXS experiment at the Ni-L3 edge.

The experimental data included here were measured at the XUV diffractometer of beamline UE46-PGM-1 at BESSY II.