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-4/ structure, we identify two novel compounds of BeP--42 and BeP-2/. 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 BeP--42 transitions to the monoclinic BeP-2/ structure. Moreover, the predicted BeP--42 and BeP-2/ phases are energetically favored compared with the BeP--3 structure synthesized experimentally. Electronic structure calculations reveal that BeP-4/, BeP--42, and BeP-2/ 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.