Sodium-Stabilized Hexagonal Borophene: Structure, Stability, and Electronic and Mechanical Properties

The crystalline form of sodium-doped hexagonal borophene (B 2 Na 2 ) has been studied using DFT calculations. The calculations predict the dynamic stability of B 2 Na 2 whose structure is a flat honeycomb boron sheet sandwiched between two sodium layers. According to estimated electronic and mechanical properties, B 2 Na 2 is a rather soft material with metallic characteristics. Evaluation of thermal stability by the molecular dynamics method indicates sufficient stability of the predicted material, which makes it possible to observe it experimentally at temperatures below 200 K.