Scanning Intrinsic Superconductivity and the Spin Hall Effect in Niobium Borides

Abstract

Although niobium borides have been extensively studied on their mechanical properties, a systematic investigation on their potential metastable phases, superconducting excitations, and spin Hall effects (SHE) is still lacking. Herein, we carry out a global structure search in the Nb-B system based on the evolutionary algorithm and density functional theory. Thermodynamical, dynamical, mechanical, and quasiharmonic approximation investigations unveil four new phases, Nb 3 B 5 , Nb 2 B 5 , Nb 3 B 7 , and Nb 5 B 4 , which are promising candidates for experimental preparations. Moreover, the superconducting transitions of all Nb-B compounds are performed from electron−phonon calculations. In addition, all Nb-B compounds are predicted to be topologically nontrivial. More intriguingly, Nb 2 B 5 is unveiled as a promising noncentrosymmetric superconductor to explore topological superconducting excitation. Furthermore, nonzero spin Hall conductivity (SHC) tensor elements of all Nb-B compounds are predicted, and NbB is predicted to own a maximal SHC value of 320 (ℏ/e) (S/cm) among all Nb-B compounds. Our theoretical results fill in the gap on superconducting and SHC parameters of Nb-B binaries, demonstrating that Nb-B binaries are a potential choice to explore superconducting excitations and topological states and to investigate the SHE.

A computational screening of Ta–Sb intermetallics at high pressure

“…As a highly effective means of fine-tuning electronic structures, the application of high pressure enables precise and continuous adjustments to both phonon and electronic energy bands. 18,23 In addition, given the fact that TaSb 2 compounds exhibiting topological properties, and encouraged by a series of recent achievements through the method of crystal structure search algorithms, [24][25][26][27] we systematically investigated the structures, topological, and superconducting properties of the predicted Ta-Sb binary phases at high pressure in this work. The high-pressure phase diagram of the Ta-Sb binary system was constructed for the first time.…”

High-Throughput Computational Screening and Design of CaPtAs-like Equiatomic Ternary Noncentrosymmetric Superconductors

“…Among the various NCSs synthesized up to date, CaPtAs stands out as an intriguing compound for displaying the unique property of exhibiting simultaneously TRS breaking and nodal superconductivity, making CaPtAs a promising candidate material for exploring and constructing novel electronic excitations, such as Majorana zero modes. , The attractive benefits offered by CaPtAs make it urgent to conduct comprehensive screening and evaluation of undiscovered compounds in structures similar to CaPtAs. Utilizing the advancements in materials databases and computational science, − this study conducted a systematic high-throughput screening. Based on data-driven evaluation and first-principles calculations on alkali and alkaline–earth-based 1:1:1 compounds with CaPtAs structure, the stabilities and electronic properties of these compounds were evaluated.…”