Using first-principles calculations, we investigate the mechanical and 

 

electronic properties of phosphorene nanosheets under tensile strains. It is found 

 

that phosphorene possesses a prominent anisotropic elasticity with the large 

 

anisotropic factor of 15.5. Along the armchair direction, the phosphorene sheet 

 

exhibits a high tensile ductility, characterized by a large elastic strain limit of 

 

0.31. While in the zigzag direction, the critical strain of phosphorene is dictated 

 

by the phonon instability and the in-plane soft mode occurs beyond the 0.22 strain. 

 

Under uniaxial strains, the band gaps of phosphorene can be modulated continuously, 

 

whose band features are also altered accordingly. A Dirac-like band structure 

 

appears in phosphorene under adequate strains along the zigzag direction. More 

 

interestingly, these Dirac cones of phosphorene display evident anisotropy, which 

 

have high Fermi velocities up to (6 - 7) x 10(5) m/s along the armchair direction 

 

but drop to zero along the zigzag direction. With such a characteristic, the 

 

strained phosphorene sheet acts as an intriguing one-dimensional metal, which 

 

enables the system many potential applications in power-efficient and ultrafast 

 

nanodevices. ((c) 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)