An oP10-FeB4 phase [H. Gou, et al., Phys. Rev. Lett, 2013, 111, 157002] was recently synthesized based on previous theoretical predictions. In this study, a high-pressure phase of FeB4 (tP10-FeB4) was proposed through first-principles calculations. The tP10-FeB4 structure, which contains two formula units per unit cell, belongs to tetragonal symmetry with the space group PA2mc. The boron atoms in tP10-FeB4 are present as tetrahedron configurations. Enthalpies as a function of pressure indicate that this new phase is probable to achieve through a phase transition from the oP10-FeB4 phase above ~65.9 GPa. The softening of acoustic phonon at T points in the Brillouin zone may be the driving force behind the phase transition. Further analyses reveal that the tP10-FeB4 phase is a potential superhard semiconductor.
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