Cornell researchers design chiral graphene

Scientists at Cornell University have developed a chiral thin film through rotational stacking of graphene sheets, the first such exploration of chirality at the nano scale. This material may be of interest in the fields of polarization optics, stereochemistry, optoelectronics and spintronics.

For the experiment,the researchers grew graphene sheets on copper, then cut them into multiple sheets. Those sheets were then stacked, with each sheet rotated slightly before being placed on the one below it. The rotation went clockwise on one stack and counter-clockwise on the other to form right-handed and left-handed stacks. Circularly polarized light – alternating left-handed and right-handed beams – were shone onto the stacks, and circular dichroism (or CD, the differential absorption of left- and right-handed light), was measured.