Ideal tensile strength of chromium by first-principles method

The ideal tensile strengths of Cr along [001], [110] and [111] directions were calculated based on the first-principles method. The results show that the ideal tensile strengths are 30.83, 37.2 and 35.49 GPa for anti-ferromagnetic Cr, while they are 33.09, 47.15 and 38.11 GPa for non-magnetic Cr along [001], [110] and [111] directions, respectively. It is obvious that [001] is the weakest direction. When the loading is applied on the direction [001], the ideal tensile strength is reached before the shear instability for both the anti-ferromagnetic and non-magnetic Cr; thus, Cr fails by cleavage and it is deemed to be intrinsically brittle. Meanwhile, for the anti-ferromagnetic Cr, the correlation between the magnetic moment and volume was analyzed, and the result shows that the magnetic moment increases with the increase in volume and eventually disappears with the increase in strain. In addition, the density of states in the process of loading was also discussed.