Altermagnetism in rare-earth intermetallics

Altermagnets are a newly-identified class of compensated magnetic materials that exhibit time-reversal symmetry-breaking responses and alternating spin splitting in the nonrelativistic band structure despite having zero net magnetization. In this work, we investigate altermagnetism in the R₂TGe₆ (R = rare earth, T = transition metal) family of compounds through a combination of thermodynamic, transport, and spectroscopic measurements on single crystals, as well as first-principle band structure calculations. The magnetization measurements show several metamagnetic transitions, and the electrical transport measurements display non-linear Hall resistivity in the paramagnetic state. Additionally, band structure calculations reveal flat bands and nodal lines as well as the characteristic spin splitting associated with altermagnetism.