  The recent discoveries of surperisingly large anomalous Hall effect in chiral
antiderromagnets have triggered extensive research efforts in various fields,
ranging from topological condensed-matter physics to antiferromagnetic
spintronics, and energy harvesting technology. However, such AHE-hosting
antiferromagnetic materials are rare in nature. Herein, we demonstrate that
Mn2.4Ga, a Fermi-level-tuned kagome antiferromagnet, has a large anomalous Hall
conductivity of about 150 {\Omega}-1cm-1 at room temperature that surpasses the
usual high values (i.e.,20-50 {\Omega}-1cm-1) observed so far in two
outstanding kagome antiferromagnets, Mn3Sn and Mn3Ge. The spin triangular
structure of Mn2.4Ga guarantees a nonzero Berry curvature while generates only
a weak net moment in the kagome plane.Moreover, the anomalous Hall conductivity
exhibits a sign reversal with the rotation of a small magnetic field, which can
be ascribed to the field-controlled chirality of the spin triangular structure.
Our theoretical calculation indicate that the large AHE in Mn2.4Ga originates
from a significantly enhanced Berry curvature associated wiht the tuning of the
Fermi level close to the Weyl points. These properties, together with the
ability to manipulate moment orientations using a moderate external magnetic
field, make Mn2.4Ga extremely exciting for future antiferromagnetic
spintronics.
