Electronic and magnetic properties of hole-doped topological kagome Fe1−xMnxSn thin films

We have investigated the electronic and magnetic structures of topological kagome ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Sn}$ ($0\ensuremath{\le}x\ensuremath{\le}0.3$) thin films via neutron diffraction, electronic transport measurements, and ab initio density functional theory (DFT) to understand the interplay between hole doping, magnetism, and the electronic structures. Temperature-dependent neutron diffraction measurements on parent FeSn reveal the N\'eel temperature to be ${T}_{\text{N}}\ensuremath{\sim}355$ K and the underlying A-type antiferromagnetic ordering is associated with a wave vector $\mathbit{q}=(0\phantom{\rule{0.16em}{0ex}}0\phantom{\rule{0.16em}{0ex}}1/2)$. Upon Mn doping to $x=0.15, {T}_{\text{N}}$ decreases slightly while the magnetic ordering vector remains the same. Resistivity measurements show metallic characteristics and in-plane anisotropy down to 10 K for all the investigated samples. The effects of hole doping are mapped in terms of electronic ground state calculations via DFT which show that the Dirac point is moved closer to the Fermi level (${E}_{\text{F}}$) and the flat bands get pushed away from ${E}_{\text{F}}$ upon hole doping. However, a comparison between hole-doped ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Sn}$ and electron-doped ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x}\mathrm{Sn}$ indicates that the N\'eel temperature does not scale with the position of ${E}_{\text{F}}$ relative to the flat band. Our results establish the antiferromagnetic state of FeSn and ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Sn}$ films at room temperature, laying the groundwork for future studies of magnetism in kagome heterostructures.