Deformation‐induced bonding evolution of iron tetraboride and its electronic origin

First‐principles density functional calculations are employed to provide a fundamental understanding of the structural features, mechanical properties, deformation behaviours and its electronic origin for the new synthesized FeB 4 . The calculated elastic moduli suggest that FeB 4 has a low compressibility, but results of ideal shear strength and theoretical hardness indicate that FeB 4 is a hard material, not a superhard material. We find that the collapse of the unique corrugated B 6 units ring in FeB 4 under deformation is responsible for the failure under tensile and shear deformation based on the calculated charge density distribution and bonding evolution. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)