In-plane canted ferromagnetism, intrinsic Weyl fermions, and large anomalous Hall effect in the kagome semimetal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Rh</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>Sn</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

Abstract

Magnetic Weyl semimetals can reveal a renowned electronic transport phenomenon, i.e., the anomalous Hall effect due to the intrinsic Berry curvature promoted by the Weyl fermions. Here, the layered kagome compound ${\mathrm{Rh}}_{3}{\mathrm{Sn}}_{2}{\mathrm{S}}_{2}$ is identified as a ferromagnetic Weyl semimetal by first-principles calculations. When the spin-orbit coupling is absent, three sets of nontrivial Weyl nodal lines emerge in the spin-up channel, while the spin-down bands are fully gapped. The obtained magnetocrystalline anisotropy energy indicates that ${\mathrm{Rh}}_{3}{\mathrm{Sn}}_{2}{\mathrm{S}}_{2}$ has an in-plane canted magnetic order with a ${30}^{\ensuremath{\circ}}$ angle to the $a$ axis. As a consequence, the spin-orbit coupling breaks the time-reversal symmetry, and the broken Weyl nodal lines give birth to one pair of Weyl points near the Fermi level. The chiral Weyl nodes, protected by the space inversion and the ${C}_{3z}$-rotation symmetry, act as the monopole source and sink of the Berry curvature and boost a large anomalous Hall conductivity approaching 580 ${\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$. This work unveils the magnetic, electronic, and topological properties as well as the anomalous Hall effect of ${\mathrm{Rh}}_{3}{\mathrm{Sn}}_{2}{\mathrm{S}}_{2}$, which will facilitate future research on the unexplored topological phenomena in ${\mathrm{Rh}}_{3}{\mathrm{Sn}}_{2}{\mathrm{S}}_{2}$.

Topics & Concepts