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 FeB4. The calculated elastic moduli suggest that FeB4 has a low compressibility, but results of ideal shear strength and theoretical hardness indicate that FeB4 is a hard material, not a superhard material. We find that the collapse of the unique corrugated B6 units ring in FeB4 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)