Tunability of the structural and magnetic transition in kagome material: PrIr$_3$B$_2$

Abstract

We report the temperature and pressure tunability of an unusual structural transformation associated with a two-step metal-insulator-metal (MIM) transition in the kagome lattice compound PrIr$_3$B$_2$ using synchrotron X-ray powder diffraction. At ambient conditions of temperature and pressure, the monoclinic ($C2/m$) and the hexagonal ($P6/mmm$) phases coexist as twinned structure in the crystal. As the temperature (pressure) is decreased (increased), PrIr$_3$B$_2$ converts fully to monoclinic structure at $T =$ 280 K (at ambient pressure) and $P =$ 1.2 GPa (at room temperature). Temperature dependence of the monoclinic structure at ambient pressure presents complex evolution of lattice parameters with weak but clearly discernable anomalies at \SI{\sim 250} {\K} and \SI{\sim 110} {\K}, which are correlated with the second MIM transition and the linear to nonlinear temperature-dependent resistivity crossover, respectively. These anomalies are likely due to some charge order state causing a partially gapped Fermi surface. The magnetic phase diagram of PrIr$_3$B$_2$ is also investigated from anisotropic measurements. At 10 K, a superzone gap opens near the antiferromagnetic transition, which does not close even in the polarized state. From the tunability of the crystal structure and magnetic and electronic ground state, promising electronic orders are indicated in this kagome metallic magnet.