  The connectivity and inherent frustration of the kagome lattice can produce
interesting electronic structures and behaviors in compounds containing this
structural motif. Here we report the properties of Pt3X2 (X = In and Tl) that
adopt a double-layer kagome net structure related to that of the topologically
nontrivial high temperature ferromagnet Fe3Sn2 and the density wave hosting
compound V3Sb2. We examined the structural and physical properties of single
crystal Pt3Tl2 and polycrystalline Pt3In2 using x-ray and neutron diffraction,
magnetic susceptibility, heat capacity, and electrical transport measurements,
along with density functional theory calculations of the electronic structure.
Our calculations show that Fermi levels lie in pseudogaps in the densities of
states with several bands contributing to transport, and this is consistent
with our Hall effect, magnetic susceptibility, and heat capacity measurements.
While electronic dispersions characteristic of simple kagome nets with
nearest-neighbor hopping are not clearly seen, likely due to the extended
nature of the Pt 5d states, we do observe moderately large and non-saturating
magnetoresistance values and quantum oscillations in the magnetoresistance and
magnetization associated with the kagome nets of Pt.
