多层黑磷中厚度和应力依赖的能隙变化研究

Band gap of few-layer black phosphorus modulated by thickness and strain

采用基于密度泛函理论的第一性原理方法研究了单层及多层黑磷晶体的能隙随层数和外加应力的变化.计算结果表明,体系能隙随着层数的增加而减小,当层数增加到10时,二维黑磷的能隙非常接近于其体材料值.层间的相互作用导致的能带劈裂是能隙减小的直接原因.应力对10层黑磷电子结构的影响也被研究.计算表明,压缩应力可以使10层黑磷从半导体转变为金属,而拉伸应力仅对能隙大小产生影响.

By using the first principle calculations based on density functional theory , the band gap of few-layer black phosphorus （ BP） is studied.The band gap depends on the layer number of black phosphorus and the epi-taxial strain.The calculated results show that the band gap will decrease with the increase of layer number in few-layer BP.The band gap of few -layer BP will be close to the value of bulk BP when layer number is up to 10. The reason that the band gap decreases is the splitting of energy bands induced by the inter -layer interactions . The influence of the strain on the electronic structures of 10-layer BP is investigated .The calculations suggest that the compressive strain results in a semiconductor -metal transition for 10 -layer BP , whereas the tensile strain only affects the values of band gaps .