Robust flat-magnetoresistivity in D03-Fe3Ga driven by chiral anomaly

Topologically non‑trivial nodes emerging from flat‑band crossings not only enhance unconventional topological responses but also play a fundamental role in exploring correlation‑driven topological physics. Here, we report the exceptionally robust chiral-anomaly-dominated transport in D03-Fe3Ga. Firstly, we observe a perfect combination of positive/negative magnetoresistance, ideal planar longitudinal magnetoresistance (PLMR), and planar Hall effect (PHE). Secondly, ultra-low-temperature resistivity exhibits pronounced non-Fermi-liquid (NFL) behavior, accompanied by the emergence of giant intrinsic anomalous Hall conductivity (AHC), in excellent agreement with our DFT calculations, which confirm the existence of tilted Weyl points arising from crossings of nearly three-dimensional (3D) flat-bands. Most remarkably, we detect an exceptionally robust flat-magnetoresistance (flat-MR) that persists without decay up to 33 T. This distinctive set of phenomena provides strong evidence that the Fermi level intersects the flattened Weyl crossings, offering unambiguous confirmation of a long-sought hallmark of ideal topological semimetals. Unlike previous systems, D03-Fe3Ga exhibits the pristine characteristics of a topological flat-band semimetal. Our findings also highlight a promising magnetic platform for quantum device innovations. While there has been extensive theoretical analysis of the 3D nodal flat-band topological semimetals, experimental realization has proved challenging. Here, Wang, Li, Zhao, Wen, and coauthors find a robust flat magnetoresistance in D03-Fe3Ga, which, combined with DFT calculations and Hall measurements, provide strong evidence that D03-Fe3Ga is a 3D nodal flat-band ferromagnet.