Metal [100] Nanowires with Negative Poisson's Ratio.
When materials are under stretching, occurrence of lateral contraction of materials is commonly observed. This is because Poisson's ratio, the quantity describes the relationship between a lateral strain and applied strain, is positive for nearly all materials. There are some reported structures and materials having negative Poisson's ratio. However, most of them are at macroscale, and reentrant structures and rigid rotating units are the main mechanisms for their negative Poisson's ratio behavior. Here, with numerical and theoretical evidence, we show that metal [100] nanowires with asymmetric cross-sections such as rectangle or ellipse can exhibit negative Poisson's ratio behavior. Furthermore, the negative Poisson's ratio behavior can be further improved by introducing a hole inside the asymmetric nanowires. We show that the surface effect inducing the asymmetric stresses inside the nanowires is a main origin of the superior property.
Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
Duc Tam
DT
Ho
School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
Soon-Yong
SY
Kwon
Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
Sung Youb
SY
Kim