Hinge-like structure induced unusual properties of black phosphorus and new strategies to improve the thermoelectric performance

• DOI: 10.1038/srep06946
• Publication Date: 2014-11-06T10:44:57Z
• Authors: Guangzhao Qin; Qing-Bo Yan; Zhenzhen Qin; Sheng-Ying Yue; Hui-Juan Cui; Qing-Rong Zheng; Gang Su
• Keywords: Condensed Matter - Materials Science; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; 02 engineering and technology; Computational Physics (physics.comp-ph); 0210 nano-technology; Physics - Computational Physics; Article

We systematically investigated the geometric, electronic and thermoelectric (TE) properties of bulk black phosphorus (BP) under strain. The hinge-like structure of BP brings unusual mechanical responses such as anisotropic Young's modulus and negative Poisson's ratio. A sensitive electronic structure of BP makes it transform among metal, direct and indirect semiconductors under strain. The maximal figure of merit $ZT$ of BP is found to be 0.72 at $800\,\mathrm{K}$ that could be enhanced to 0.87 by exerting an appropriate strain, revealing BP could be a potential medium-high temperature TE material. Such strain-induced enhancements of TE performance are often observed to occur at the boundary of the direct-indirect band gap transition, which can be attributed to the increase of degeneracy of energy valleys at the transition point. By comparing the structure of BP with SnSe, a family of potential TE materials with hinge-like structure are suggested. This study not only exposes various novel properties of BP under strain, but also proposes effective strategies to seek for better TE materials.<br/>6 figures. Supplemental Information is available in Scientific Reports and also involved in this source package<br/>