▎ 摘　　要

We evaluate the effect of stretching on the optical conductance of graphene. It is found that the low energy (Dirac regime) isotropy that leads to the "universal conductance" is lost. More significantly, due to the loss of C-3 symmetry, a nonzero Hall conductance emerges for stretching along chiral directions, reaching a maximum at a stretching angle of 45 degrees, and being as high as sigma(0)=e(2)/4 (h) over bar at van Hove singular point for bond angle changes of about 2 degrees. Our results indicate that the optical properties of graphene can be tuned by a weak mechanical deformation. (C) 2009 American Institute of Physics. [doi:10.1063/1.3251074]