Chemical control of magnetism in the Kagome metal CoSn<sub>1-x</sub>In<sub>x</sub>: Magnetic order from nonmagnetic substitutions
ORAL
Abstract
The Pauli paramagnet, CoSn consists of Kagome layers of Co, which generates flat bands and a
large density of states near the Fermi energy. When the Fermi energy is positioned within these
bands large electronic instabilities can result. For the Kagome metal, CoSn, this alignment is not
realized and the flat bands are completely filled. We demonstrate that replacing Sn with In
moves the flat bands into the Fermi energy, as expected from simple electron counting. This is
supported by band structure calculations, heat capacity measurements, and angle-resolved
photoemission spectroscopy. The increased density of states results in the emergence of
antiferromagnetic order as evidenced in magnetic susceptibility, Mossbauer spectroscopy and
neutron diffraction data. The Neel temperature reaches a maximum of 32 K for x = 0.4.
Emergence of magnetic order when doping a non-magnetic element, In, into a non-magnetic
Kagome metal is striking. This work provides clear evidence that flat bands from electronically
frustrated lattices in bulk crystals provide a new and powerful way to realize correlated ground
states controlled by crystal chemistry. The effects of hole doping with Fe or Ga will be discussed
as well.
large density of states near the Fermi energy. When the Fermi energy is positioned within these
bands large electronic instabilities can result. For the Kagome metal, CoSn, this alignment is not
realized and the flat bands are completely filled. We demonstrate that replacing Sn with In
moves the flat bands into the Fermi energy, as expected from simple electron counting. This is
supported by band structure calculations, heat capacity measurements, and angle-resolved
photoemission spectroscopy. The increased density of states results in the emergence of
antiferromagnetic order as evidenced in magnetic susceptibility, Mossbauer spectroscopy and
neutron diffraction data. The Neel temperature reaches a maximum of 32 K for x = 0.4.
Emergence of magnetic order when doping a non-magnetic element, In, into a non-magnetic
Kagome metal is striking. This work provides clear evidence that flat bands from electronically
frustrated lattices in bulk crystals provide a new and powerful way to realize correlated ground
states controlled by crystal chemistry. The effects of hole doping with Fe or Ga will be discussed
as well.
*This research was supported by the U.S. Department of Energy, Office of Science, Basic EnergySciences, Materials Sciences and Engineering Division.
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Publication: B.C. Sales et al. Chem. Mat. 34, 7069 (2022)
Presenters
-
Brian C Sales
- OAK RIDGE NATIONAL LABORATORY