Altermagnetic-type noncollinear magnets on the maple leaf lattice

We define unconventional non-collinear magnetic ground states on the maple leaf lattice (MLL) distinguished by the selective breaking or preservation of time reversal (T) and parity (P). Depending on the nature of PT-breaking, linear spin-wave theory reveals momentum-dependent non-relativistic magnon spin splitting at different high symmetry points in the Brillouin zone. From a mean-field analysis of the Hubbard model at weak coupling, we reveal itinerant P-preserving $q=0$ altermagnetic (AlM)-type order, while we expect P-broken canted-120^∘ AlM-type order at strong coupling. Our findings establish the MLL as a prime platform for exploring phase transitions and frustration phenomena emanating from competing non-collinear AlM-type orders.