High-quality single crystals of the kagome metals Ni$_3$In and Ni$_3$Sn grown from Pb flux

Abstract

The bilayer kagome metal Ni$_3$In has recently attracted attention due to the presence of a flat band located near the Fermi level, which has been associated with unconventional thermodynamic and electronic transport properties [Ye et al., Nat. Phys. 20, 610-614 (2024)]. However, further investigation of the intrinsic properties of this system has been hindered by the lack of large, high-quality single crystals. Here, we report the successful growth of Ni$_3$(In, Sn) single crystals using a Pb-flux technique. By optimizing the growth conditions, competing binary phases can be effectively suppressed, enabling the synthesis of single crystals with dimensions reaching several millimeters. We compare the physical properties of our Pb-flux-grown crystals to previously reported samples prepared by iodine-assisted chemical vapor transport and molecular beam epitaxy as well as to first-principles resistivity calculations. We find a significantly lower electrical resistivity in our crystals, in excellent agreement with calculations of resistivity from electron-phonon scattering, a sizeable non-saturating magnetoresistance, and a reduced Sommerfeld coefficient and magnetic susceptibility compared to previous experimental findings, which are likely related to differences in the Fermi level position. Our results establish Pb-flux growth as a reliable route for obtaining large single crystals of the bilayer kagome metals Ni$_3$(In, Sn) that are suitable for further thermodynamic and spectroscopic investigations of their intrinsic electronic and magnetic properties.