Ternary Bismuthide SrPtBi2: Computation and Experiment in Synergism to Explore Solid-State Materials

TL;DR

This study combines theoretical calculations and experimental synthesis to discover and characterize a new ternary bismuthide, SrPtBi2, revealing its stable orthorhombic structure and metallic properties.

Contribution

It is the first successful synthesis and structural confirmation of SrPtBi2, demonstrating the effectiveness of combined computational and experimental approaches in discovering new solid-state materials.

Findings

SrPtBi2 is thermodynamically stable and crystallizes in space group Pnma.

The compound exhibits metallic properties with low electron-phonon interactions.

Pt-Bi interactions are crucial for the structural stability of SrPtBi2.

Abstract

A combination of theoretical calculation and the experimental synthesis to explore the new ternary compound is demonstrated in the Sr-Pt-Bi system. Since Pt-Bi is considered as a new critical charge-transfer pair for superconductivity, it inspired us to investigate the Sr-Pt-Bi system. With a thorough calculation of all the known stable/metastable compounds in the Sr-Pt-Bi system and crystal structure predictions, the thermodynamic stability of hypothetical stoichiometry, SrPtBi2, is determined. Followed by the high-temperature synthesis and crystallographic analysis, the first ternary bismuthide in Sr-Pt-Bi, SrPtBi2 was prepared and the stoichiometry was confirmed experimentally. SrPtBi2 crystallizes in the space group Pnma (S.G. 62, Pearson Symbol oP48), which matches well with theoretical prediction using an adaptive genetic algorithm (AGA). Using first-principles calculations, we demonstrate that the orthorhombic structure has lower formation energies than other 112 structure types, such as tetragonal BaMnBi2 (CuSmP2) and LaAuBi2 (CuHfSi2) structure types. The bonding analysis indicates the Pt-Bi interactions play a critical role in structural stability. The physical properties measurements show the metallic properties with low electron-phonon interactions at the low temperature, which agrees with the electronic structure assessment.