“…In two dimensions (2D), many antiferromagnetic materials with a triangular lattice motif can harbor frustrated interactions, making them excellent candidates for exotic behavior including quantized magnetization plateaus [5], charge frustration in mixed-valence spinels [6,7], order by disorder [8], valencebond ordering [9,10], 'molecule-like spin clusters [11,12], and potentially spin-liquid states. [4,[13][14][15][16][17] Despite a plethora of theoretical predictions, only a few highly-frustrated candidates have been investigated in detail so far. [3,4,14,17] For instance, in three dimensions (3D), corner-sharing tetrahedral pyrochlores A 2 B 2 O 7 with spins coupled either ferromagnetically or antiferromagnetically have been proposed to host numerous interesting phenomena stemming from macroscopic ground state degeneracy.…”