Hu Yanxiao, Li Ding, Feng Chunbao, Li Shichang, Chen Bole, Li Dengfeng, Zhang Gang
School of Science, Chongqing University of Posts and Telecommunications, Chongqing, 400065, China.
Institute of High Performance Computing, A*STAR, 138632, Singapore.
Phys Chem Chem Phys. 2022 Jun 29;24(25):15340-15348. doi: 10.1039/d2cp01745h.
Two-dimensional diamond, also called diamane, has attracted great research attention for its novel physical properties and potential applications in nanoelectronics, ultrasensitive resonators and thermal management. Compared with the hexagonal diamane, the physical properties of the rectangular diamane are less explored. In this work, using first-principles calculations, we conducted a comprehensive study on the electronic, phononic, thermal and mechanical properties of three types of rectangular diamanes. We found that rectangular diamanes possess a high Debye temperature (722-788 K) and a strong in-plane Young's modulus (405.9-575.9 N m). We further show close to zero Poisson's ratio in the rectangular diamane. Moreover, based on the phonon Boltzmann transport equation, high room temperature lattice thermal conductivity (910-1807 W m K) and strong configuration and orientation dependence are demonstrated. Phonon group velocity, relaxation time and characteristic square velocity are explored and it is demonstrated that phonon harmonic behavior is responsible for the remarkable configuration dependent thermal conductivity in rectangular diamanes. The present work underscores the use of nanostructure engineering to manipulate thermal conductivity of 2D diamond, which provides opportunities for developing effective thermal channeling devices.
二维金刚石，也称为二亚甲基金刚石，因其新颖的物理性质以及在纳米电子学、超灵敏谐振器和热管理方面的潜在应用而备受研究关注。与六方二亚甲基金刚石相比，矩形二亚甲基金刚石的物理性质研究较少。在这项工作中，我们采用第一性原理计算，对三种类型的矩形二亚甲基金刚石的电子、声子、热和力学性质进行了全面研究。我们发现矩形二亚甲基金刚石具有较高的德拜温度（722 - 788 K）和面内杨氏模量（405.9 - 575.9 N/m）。我们还进一步表明矩形二亚甲基金刚石的泊松比接近零。此外，基于声子玻尔兹曼输运方程，证明了其在室温下具有较高的晶格热导率（910 - 1807 W/(m·K)）以及强烈的构型和取向依赖性。我们对声子群速度、弛豫时间和特征平方速度进行了探索，并证明声子的谐波行为是矩形二亚甲基金刚石中显著的构型依赖性热导率的原因。本工作强调了利用纳米结构工程来调控二维金刚石的热导率，这为开发有效的热通道器件提供了机会。
