Du Junyi, Sun Weiguo, Li Xiaofeng, Su Xinfang
College of Mathematical Sciences, Luoyang Normal University, Luoyang 471934, China.
College of Physics and Electronic Information & Henan Key Laboratory of Electromagnetic Transformation and Detection, Luoyang Normal University, Luoyang 471934, China.
Materials (Basel). 2025 Jul 1;18(13):3125. doi: 10.3390/ma18133125.
Transition metal borides have garnered significant research interest due to their versatile properties, including superconductivity and exceptional hardness. This study examines the stable crystal structures of Rhodium-Boron (Rh-B) compounds under high pressure using first-principles structural searching. Beyond the previously known RhB, RhB, and RhB phases, three new boron-rich phases-C2/m-RhB, Amm2-RhB, and Cmca-RhB-are identified, each characterized by three-dimensional covalent bonding networks. Their mechanical and thermodynamic stability is validated through elastic property assessments and phonon dispersion calculations. Surprisingly, these phases exhibit low bulk and shear moduli, ruling them out as candidates for hard materials. The metallic character of these borides is evident from their electronic density of states, which exhibits a sharp peak at the -a signature often associated with superconducting systems. Indeed, our calculations predict values of 8.93 K and 9.36 K for Amm2-RhB and Cmca-RhB, respectively, at 100 GPa.
过渡金属硼化物因其多种特性，包括超导性和极高硬度，而引起了广泛的研究兴趣。本研究采用第一性原理结构搜索方法，研究了铑硼（Rh-B）化合物在高压下的稳定晶体结构。除了先前已知的RhB、RhB和RhB相之外，还发现了三个新的富硼相——C2/m-RhB、Amm2-RhB和Cmca-RhB，每个相都具有三维共价键网络特征。通过弹性性能评估和声子色散计算验证了它们的力学和热力学稳定性。令人惊讶的是，这些相的体模量和剪切模量较低，因此排除了它们作为硬质材料候选者的可能性。这些硼化物的金属特性从其电子态密度中明显可见，其在-处呈现出一个尖锐的峰值，这是超导系统常有的特征。实际上，我们的计算预测，在100 GPa时，Amm2-RhB和Cmca-RhB的超导转变温度分别为8.93 K和9.36 K。
