Pressure-Induced Formation of Intermetallic CrBi2

Binary transition-metal bismuth compounds offer a new class of solid-state materials with emergent properties such as magnetism, superconductivity, thermoelectricity and nontrivial topology. Under ambient conditions, Bi shows immiscibility with many other elements. High-pressure can offers an alternative thermodynamic landscape for Bi-based intermetallic systems. Herein, we computationally explore the energy landscape for the immiscible Cr-Bi systems under high-pressure. At 60 GPa, CrBi2 having a CuAl2-type structure with -Cr-Cr-Cr- chains and Bi2 dimers is found to be thermodynamically stable with respect to the elemental solids. The structure is dynamically stable and exhibits ferromagnetic character. Furthermore, electronic structure calculation reveals notable Cr-Cr and Bi-Bi bonding interaction, along with distinctive Cr 3d and Bi 6p bonding interaction. Apart from homoatomic interactions, Cr 3d and Bi 6p hybridization plays a critical role in stabilizing CrBi2 under pressure. This finding provides a viable route towards discovery of new binary intermetallic compounds and extend the compositional space for chemical synthesis at high-pressure.