Resonant bonding driven giant phonon anharmonicity and low thermal conductivity of phosphorene
Resonant bonding driven giant phonon anharmonicity and low thermal conductivity of phosphorene
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DOI：
10.1103/physrevb.94.165445
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发表时间：
2016-10-26
影响因子：
3.7
通讯作者：
Hu, Ming
中科院分区：
文献类型：
--
作者：
Qin, Guangzhao;Zhang, Xiaoliang;Hu, Ming
二维磷烯具有不同于其他二维材料的独特物理和化学性质，其在纳米、光电子和热电等领域的应用日益广泛，需要对其热输运性质有一个基本的认识。然而，即使是基本的声子性质，例如，在文献中报道的磷烯的晶格热导率（κ）的精确值，可以相差一个数量级，这是不可接受的。更重要的是，其独特性质（如强声子非谐性和不寻常的各向异性）的基础物理仍然是未知的。基于第一性原理对磷烯的电子结构和晶格动力学的分析，我们发现磷烯中的巨声子非谐性与软横光学（TO）声子模有关，是由轨道控制的共振成键驱动的长程相互作用引起的.我们还提供了一个连接各向异性和低的微观图片。的磷烯的巨定向声子非谐性和长程相互作用，这进一步追溯到不对称的共振轨道占领的电子和铰链状结构的特点。不含糊的低。用三种独立的从头算方法一致地得到了磷烯的声子谱，在很大程度上证实了声子的非谐性，有望结束以往研究中令人困惑的巨大偏差。这项工作进一步明确了包括货车德瓦耳斯相互作用的必要性，以准确地描述磷烯的原子间相互作用。我们建议在2D材料中，谐振键合导致低热导率，尽管它最初是在三维（3D）热电和相变材料中发现的。我们的研究从轨道态的角度提供了对声子输运的见解，这将对新兴的基于磷烯的纳米器件的设计具有重要意义。
Two-dimensional (2D) phosphorene, which possesses fascinating physical and chemical properties distinctively different from other 2D materials, calls for a fundamental understanding of thermal transport properties for its rapidly growing applications in nano- and optoelectronics and thermoelectrics. However, even the basic phonon property, for example, the exact value of the lattice thermal conductivity (kappa) of phosphorene reported in the literature, can differ unacceptably by one order of magnitude. More importantly, the fundamental physics underlying its unique properties such as strong phonon anharmonicity and unusual anisotropy remains largely unknown. In this paper, based on the analysis of electronic structure and lattice dynamics from first principles, we report that the giant phonon anharmonicity in phosphorene is associated with the soft transverse optical (TO) phonon modes and arises from the long-range interactions driven by the orbital governed resonant bonding. We also provide a microscopic picture connecting the anisotropic and low. of phosphorene to the giant directional phonon anharmonicity and long-range interactions, which are further traced back to the asymmetric resonant orbital occupations of electrons and characteristics of the hinge-like structure. The unambiguously low. of phosphorene obtained consistently by three independent ab initio methods confirms the phonon anharmonicity to a large extent and is expected to end the confusing huge deviations in previous studies. This work further pinpoints the necessity of including van der Waals interactions to accurately describe the interatomic interactions in phosphorene. We propose in 2D material that resonant bonding leads to low thermal conductivity, despite that it is originally found in three-dimensional (3D) thermoelectric and phase-change materials. Our study offers insights into phonon transport from the view of orbital states, which would be of great significance to the design of emerging phosphorene-based nanodevices.