Abstract
New, stable stoichiometries in Be-P systems are investigated up to 100 GPa by the CALYPSO structure prediction method. Along with the BeP2-I41/amd structure, we identify two novel compounds of Be3P2-P-421m and Be3P2-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 Be3P2-P-421m transitions to the monoclinic Be3P2-C2/m structure. Moreover, the predicted Be3P2-P-421m and Be3P2-C2/m phases are energetically favored compared with the Be3P2-Ia-3 structure synthesized experimentally. Electronic structure calculations reveal that BeP2-I41/amd, Be3P2-P-421m, and Be3P2-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.
Highlights
An important part of computational materials science is predicting novel forms of materials and describing their different characteristics, which are influenced by their electronic structures
We provide a detailed discussion of the methods of our calculations and the results obtained, including structural parameters, electronic band structure, density of states (DOS), and bonding character of the beryllium phosphide systems
The projector augmented wave (PAW) pseudopotential employing Perdew– Burke–Ernzerh (PBE) and the band structures of Be-P phases are computed using the Heyd– Scuseria–Ernzerhof (HSE) hybrid functional, in order to evade the innate weakness of generalized gradient approximation (GGA) when handling the band structures of semiconducting materials [39]
Summary
An important part of computational materials science is predicting novel forms of materials and describing their different characteristics, which are influenced by their electronic structures. The III–V group phosphides and nitrides [5] have received the most attention, the II–V group compounds are being investigated for optoelectronic applications [6,7,8] These compounds have abundant semiconductor properties [9,10,11] and crystallize in several phases [12,13]. There is ongoing debate over the stoichiometric composition of Ca3P2, and an experimental study on the thermodynamic properties of this compound has been published [15] Compared with their calcium and magnesium counterparts, beryllium phosphides have received little theoretical or experimental attention [16,17,18,19,20,21]. It is of the utmost importance to perform a thorough investigation of the crystal structure with varied beryllium phosphide stoichiometries and to explore the associated bonding properties under pressure. Our results are of great significance for the further study of the structures and properties of Be-P system under high pressures
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