2D materials

The Poisson's ratio characterizes the resultant strain in the lateral direction for a material under longitudinal deformation.  Though negative Poisson's ratios (NPR) are theoretically possible within continuum elasticity, they are most frequently observed in engineered materials and structures, as they are not intrinsic to many materials.  In this work, we report NPR in single-layer graphene ribbons, which results from the compressive edge stress induced warping of the edges.

Shuze Zhu* and Teng Li*, Strain-induced programmable half-metal and spin-gapless semiconductor in an edge-doped boron nitride nanoribbon, Physical Review B, 93, 115401 (2016)