Chowdhury Suman, Demin Victor A, Chernozatonskii Leonid A, Kvashnin Alexander G
Department of Physics, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida 201314, Uttar Pradesh, India.
Emanuel Institute of Biochemical Physics RAS, 4 Kosygin Street, 119334 Moscow, Russia.
Membranes (Basel). 2022 Sep 25;12(10):925. doi: 10.3390/membranes12100925.
Ultra-thin diamond membranes, diamanes, are one of the most intriguing quasi-2D films, combining unique mechanical, electronic and optical properties. At present, diamanes have been obtained from bi- or few-layer graphene in AA- and AB-stacking by full hydrogenation or fluorination. Here, we study the thermal conductivity of diamanes obtained from bi-layer graphene with twist angle θ between layers forming a Moiré pattern. The combination of DFT calculations and machine learning interatomic potentials makes it possible to perform calculations of the lattice thermal conductivity of such diamanes with twist angles θ of 13.2∘, 21.8∘ and 27.8∘ using the solution of the phonon Boltzmann transport equation. Obtained results show that Moiré diamanes exhibit a wide variety of thermal properties depending on the twist angle, namely a sharp decrease in thermal conductivity from high for "untwisted" diamanes to ultra-low values when the twist angle tends to 30∘, especially for hydrogenated Moiré diamanes. This effect is associated with high anharmonicity and scattering of phonons related to a strong symmetry breaking of the atomic structure of Moiré diamanes compared with untwisted ones.
超薄金刚石膜，即二胺，是最具吸引力的准二维薄膜之一，它兼具独特的机械、电子和光学性质。目前，二胺是通过双层或少数层石墨烯在AA和AB堆叠结构下进行完全氢化或氟化而得到的。在此，我们研究了由双层石墨烯形成莫尔图案时层间扭转角θ所得到的二胺的热导率。密度泛函理论（DFT）计算与机器学习原子间势相结合，使得利用声子玻尔兹曼输运方程的解来计算扭转角θ为13.2°、21.8°和27.8°的此类二胺的晶格热导率成为可能。所得结果表明，莫尔二胺根据扭转角呈现出各种各样的热性质，即热导率从“未扭转”二胺的高值急剧下降到扭转角趋于30°时的超低值，尤其是对于氢化莫尔二胺。这种效应与莫尔二胺原子结构相对于未扭转二胺的强烈对称性破缺相关的高声子非谐性和散射有关。
