First-Principles Study of High-Pressure Phase Stability and Electron Properties of Be-P Compounds

New, stable stoichiometries in Be-P systems are investigated up to 100 GPa by the CALYPSO structure prediction method. Along with the BeP(2)-I4(1)/amd structure, we identify two novel compounds of Be(3)P(2)-P-42(1)m and Be(3)P(2)-C2/m. It should be noted that the Be-P compounds are predicted to be energetically unfavorable above 40 GPa. As can be seen, interesting structures may be experimentally synthesizable at modest pressure. Our results indicate that at 33.2 GPa, the most stable ambient-pressure tetragonal Be(3)P(2)-P-42(1)m transitions to the monoclinic Be(3)P(2)-C2/m structure. Moreover, the predicted Be(3)P(2)-P-42(1)m and Be(3)P(2)-C2/m phases are energetically favored compared with the Be(3)P(2)-Ia-3 structure synthesized experimentally. Electronic structure calculations reveal that BeP(2)-I4(1)/amd, Be(3)P(2)-P-42(1)m, and Be(3)P(2)-C2/m are all semiconductors with a narrow band gap. The present findings offer insight and guidance for exploration toward further fundamental understanding and potential applications in the semiconductor field.