Large anomalous Hall effect in the kagome ferromagnet LiMn6Sn6

Kagome magnets are believed to have numerous exotic physical properties due to the possible interplay between lattice geometry, electron correlation and band topology. Here, we report the large anomalous Hall effect in the kagome ferromagnet LiMn6Sn6, which has a Curie temperature of 382 K and easy plane along with the kagome lattice. At low temperatures, unsaturated positive magnetoresistance and opposite signs of ordinary Hall coefficient for rho(xz) and rho(yx) indicate the coexistence of electrons and holes in the system. A large intrinsic anomalous Hall conductivity of 380 Omega(-1) cm(-1), or 0.44 e(2)/h per Mn layer, is observed in sigma(A)(xy). This value is significantly larger than those in other RMn6Sn6 (R = rare earth elements) kagome compounds. Band structure calculations show several band crossings, including a spin-polarized Dirac point at the K point, close to the Fermi energy. The calculated intrinsic Hall conductivity agrees well with the experimental value, and shows a maximum peak near the Fermi energy. We attribute the large anomalous Hall effect in LiMn6Sn6 to the band crossings closely located near the Fermi energy.