磷烯的力场参数拟合及声子输运性质的理论研究

Since the first exfoliation of monolayer graphene, two dimensional materials have been becoming an attractive topic due to their unique structures and fascinating physical and chemical properties. Another emergent 2D material, phosphorene, has attracted enormous attention, which overcomes the weakness of graphene and MoS2. Understanding of phonon transport properties of phosphorene is vital for its application in nano-electronics, phononic devices, and thermoelectrics. However, the lack of accurate interatomic empirical potential/force field has greatly limited the studies on their thermal transport properties. In this proposal, we will try to parameterize a CLASS2 force filed for phosphorene. And then, the thermal conductivities of few layer phosphorenes will be explored as well as one dimensional phosphorene nanoribbons. The emphasis will be placed on understanding the mechanism of phonon scattering due to interlayer van der Waals interaction, quantum confinement effect, edge roughness, and defects, from which the efficient methods to tune the thermal conductivity of phosphorene can be obtained. This project is helpful for expanding the applications of phosphorene.

因其独特的结构和物性、丰富的科学内涵及广阔的应用前景，二维材料已经成为近年来科学研究的焦点。新近发现的二维单层磷烯克服了石墨烯零带隙的缺陷以及二硫化钼载流子迁移率相对较低的缺点，成为当前的明星材料。磷烯作为半导体材料，研究声子输运性质对于探索其在电子学和声子学器件、热电方面的应用起着重要的作用。然而目前能够精确描述磷原子间相互作用的经验势仍然较欠缺，这极大地限制了磷烯声子输运性质的研究。本申请拟采用CLASS2力场来精确描述磷原子间作用势，进而研究二维单/多层磷烯以及一维磷烯纳米带的热输运性质，探索调控热导率的方法，理解声子散射机理，揭示层间范德华力、量子限域效应、边界粗糙程度和空位缺陷等因素对于声子自由程的影响。这些理论研究有助于拓宽磷烯的应用范围，并为实验方面探索磷烯的实际应用提供有价值的理论指导和依据。

因其独特的结构和物性、丰富的科学内涵及广阔的应用前景，二维材料已经成为近年来国际前沿科学研究的焦点。新近发现的二维单层磷烯克服了石墨烯零带隙的缺陷以及二硫化钼载流子迁移率较低的缺点，成为当前的明星材料。作为半导体材料，声子输运性质对于磷烯在电子学和声子学器件、热电方面的应用起着重要的作用。本项目采用CLASS2力场来精确描述磷原子间作用势，通过遗传算法结合Simplex算法参数化了黑磷烯和蓝磷烯的力场模型，得到的参数能够非常好地描述磷烯的晶格振动性质和力学性质。我们还利用非平衡分子动力学方法研究了二维单层磷烯以及一维磷烯纳米带的热输运性质，探索调控热导率方法，比如量子限域效应和边界粗糙层度对于热导率的削弱作用，并分析了背后的机理。边界粗糙化不仅极大地制约了磷烯的传热能力，而且抑制了热导率随着样品长度发散的反常特性，这意味着边界粗糙化对于长波声子也能起到非常显著的散射作用。这些理论研究将有助于拓宽磷烯的应用范围，并为实验方面探索磷烯的实际应用提供理论指导和依据。