Pressure and Strain Effects on the Structural, Electronic, and Optical Properties of K4 Phosphorus

An investigation of the mechanical, electronic, and optical properties of the recently reported material K4 phosphorus was made in this work. K4 phosphorus has been proved to be mechanically and dynamically stable up to 7 GPa under hydrostatic pressure. We compared the elastic anisotropy, average acoustic velocity, and Debye temperature of K4 phosphorus at 0 and 7 GPa. The ideal tensile properties at large strains of K4 phosphorus were also examined, with the results showing that it would cleave under the tensile strength of 8.5 GPa with the strain of 0.3. In addition, the effect of tensile strain and pressure on optical properties and band gap were studied.