Abstract: The best place to discover new physics is in new materials, which is especially true in strongly spin-orbit-coupled transition metal materials where competing interactions with comparable strength are intertwined together. In this talk, I will briefly introduce two systems where quantum states defy all existing theoretical mechanisms and experimental precedents have been observed.

The first system consists of a series of highly lattice-sensitive trimer lattice iridates Ba_3n+1Ir_3nO_9n+1 (n = 1, 2, ∞) that covers the extreme ends of a magnetic spectrum: the delicate quantum liquid driven by a new frustration mechanism (Ba₄Ir­₃O₁₀, n = 1) on one end and an antiferromagnet with T_N = 183 K (BaIrO₃, n = ∞) on the other.

The second system, the ferrimagnetic insulator Mn₃Si₂Te₆ showcases an unusual colossal magnetoresistance that occurs only when a magnetic polarization is avoided, which challenges all existing models and precedents. With evidence from neutron scattering and electric-current controlled measurements, we report that this quantum state is driven by chiral orbital currents (COC) flowing along the edges of the MnTe₆ octahedra.