Crystal Growth of Pnictide Superconductors with Novel Electronic Order and Elastic Response

In this contribution, I will focus on three families of materials, BaNi2(As1-xPx)2 [1], FeSe1-xSx [2] and CrAs1-xPx [3], that show rich phase diagrams containing nearly degenerate electronic states. In these materials the electronic properties (e.g. nematicity, charge- and magnetic ordering) can be altered by tuning the interplay between the structural and electronic degrees of freedom, for instance by chemical doping or by applying hydrostatic pressure. The prerequisite for detailed experimental exploration, is the design and crystal growth of high-quality singly crystals.
We have been implementing chemical vapour transport and crystallisation by flux for the growth of the selected materials enabling us to study the phenomena of interest under well-controlled conditions. A series of high-quality single crystals of BaNi2(As1-xPx)2, FeSe1-xSx and CrAs1-xPx have been grown and characterised by chemical analysis, x-ray diffraction and magnetic measurements (see Figure 1). Furthermore, we have carefully monitored the doping dependence of various electronic phases in these materials and tracked the pressure-temperature dependent changes in the crystal structure.