  Zintl phases, containing strongly covalently bonded frameworks with separate
ionically bonded ions, have emerged as a critical materials family in which to
couple magnetism and strong spin-orbit coupling to drive diverse topological
phases of matter. Here we report the single-crystal synthesis, magnetic,
thermodynamic, transport, and theoretical properties of the Zintl compound
EuZn2P2 that crystallizes in the anti-La2O3 P-3m1 structure, containing
triangular layers of Eu2+ ions. In-plane resistivity measurements reveal
insulating behavior with an estimated bandgap of Eg=0.11eV. Comparing Eu
magnetic ordering temperatures across trigonal EuM2X2 (M=divalent metal,
X=pnictide) shows that EuZn2P2 exhibits the highest ordering temperature, with
variations in TN correlating with changes in expected dipolar interaction
strengths within and between layers and independent of the magnitude of
electrical conductivity. These results provide experimental validation of the
cytochemical intuition that the cation Eu2+ layers and the anionic (M2X2)2-
framework can be treated as electronically distinct subunits, enabling further
predictive materials design.
