CoSn is a Pauli paramagnet with relatively flat $d$ bands centered about 100 meV below the Fermi energy, $E_F$. Single crystals of CoSn lightly doped with Fe, In, or Ni are investigated using x-ray and neutron scattering, magnetic susceptibility and magnetization, AC susceptibility, specific heat, and resistivity measurements. Within the rigid-band approximation, hole doping with a few percent of Fe or In should move the flat bands closer to $E_F$, whereas electron doping with Ni should move the flat bands further away from $E_F$. We provide evidence that this indeed occurs. Fe and In doping drive CoSn toward magnetism, while Ni doping suppresses CoSn's already weak magnetic response. The resulting ground state is different for Fe versus In doping. For Fe-doped crystals, ${\mathrm{Co}}_{1-x}{\mathrm{Fe}}_x\mathrm{Sn}$, with $0.02<x<0.27$, the magnetic and specific-heat data are consistent with the formation of a spin glass, with a glass temperature, $T_g$, ranging from 1 K for $x=0.02$ to 10 K for $x=0.27$. Powder and single-crystal neutron diffraction found no evidence of long-range magnetic order below $T_g$ for samples with $x\approx 0.17$. For In-doped crystals, $\mathrm{Co}{\mathrm{Sn}}_{1-y}{\mathrm{In}}_y$, both the magnetic susceptibility and the Sommerfeld coefficient, γ, increase substantially relative to pure CoSn, but with no clear indication of a magnetic transition for $0.05<y<0.2$. CoSn crystals doped with Ni (${\mathrm{Co}}_{0.93}{\mathrm{Ni}}_{0.07}\mathrm{Sn}$) have a significantly smaller magnetic susceptibility and γ than pure CoSn, consistent with flat bands further from $E_F$.

中文翻译：

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用Fe，In或Ni掺杂来调整kagome金属CoSn的平带

CoSn是泡利（Pauli）顺磁体，相对扁平 $d$ 能带的中心比费米能量低约100 meV， $E_F$。使用X射线和中子散射，磁化率和磁化强度，AC磁化率，比热和电阻率测量研究了轻掺杂Fe，In或Ni的CoSn单晶。在刚性带近似值范围内，掺有少量Fe或In的空穴掺杂应使平坦带更靠近$E_F$，而用Ni掺杂的电子应将平带移到更远的地方 $E_F$。我们提供证据证明确实存在这种情况。Fe和In掺杂会驱使CoSn趋向磁性，而Ni掺杂会抑制CoSn已经很弱的磁响应。Fe和In掺杂产生的基态不同。对于掺铁晶体，${\mathrm{有限公司}}_{\mathrm{1个}-X}{铁}_X锡$， 和 $0.02<X<0.27$，磁和比热数据与自旋玻璃的形成，玻璃温度， ${Ť}_G$，范围从1 K $X=0.02$ 至10 K $X=0.27$。粉末和单晶中子衍射未发现以下远距离磁阶的证据${Ť}_G$ 用于带有 $X\approx 0.17$。对于In掺杂的晶体，$\mathrm{有限公司}{锡}_{\mathrm{1个}-ÿ}{在}_{ÿ}$，磁化率和Sommerfeld系数γ均相对于纯CoSn显着增加，但没有明确表明$0.05<ÿ<0.2$。掺Ni的CoSn晶体（${\mathrm{有限公司}}_{0.93}{你}_{0.07}锡$）的磁化率和γ值比纯CoSn小得多，这与离$E_F$。