First-principle Study Of Thermal Transport Properties Of Two-dimensional Carbon Materials

Since scientists successfully constructed graphene,based on the series of excellent physical properties of graphene,researchers put much focus on two-dimensional materials.The research on the thermal transport of two-dimensional materials has always been one of the hotspots.Carbon can form many allotropes,which provides ideal material platforms for us to study the thermal transport properties of materials.Thermal transport is the most fundamental physical property of materials.According to the white paper released by China,environmental issues are still a thorny issue facing social development,new and green materials are needed to relieve the increasingly strained resource situation.With the rapid development of supercomputers in China,more and more researchers are using theoretical calculation methods to find new materials with excellent performance.In this paper,the thermal transport properties of two-dimensional carbon materials are studied based on the first principles.In this paper,by using first-principles simulations,we investigate the intrinsic phonon transport characters of three sp²-hybrid 2D carbon materials.At room temperature,the lattice thermal conductivity of hybrid Kagome graphene and Kagome graphene is about 445 Wm^-1K^-1 and 42 Wm^-1K^-1,which is merely 15.8%and 1.5%of that of graphene.We attribute these distinct properties to the obvious phonon flat bands in the phonon spectra of Kagome structure owing to the intrinsic localized vibration ring.For further understand the suppression of thermal conductivity in Kagome lattice,we decompose the phonon mode properties and find that the low group velocity caused by the flat band and the lattice distortion caused by the Kagome lattice are the main origins for the obvious suppression of thermal conductivity.The results presented in this work shed light on the lattice thermal conductivity of graphene allotropes with Kagome lattice and could provide a viable way to modulate the thermal conductivity of2D materials.In addition,Recently,two two-dimensional carbon materials,called AFI and HGY have been successfully prepared,while the research on thermal transport has not been reported.The thermal transport properties of these two materials are calculated systematically by solving Boltzmann transport equation and combining first principles.At 300K,the lattice thermal conductivity of HGY is 177.56 Wm^-1K^-1,AFI is 246.83Wm^-1K^-1.The lattice thermal conductivity of AFI and HGY is less than one-tenth of that of graphene.Our work can provide some references for the study of the thermal transport properties of two-dimensional carbon materials.The thermal transport properties of a series of two-dimensional carbon materials are studied based on first principles calculation and a feasible method to regulate the thermal conductivity of lattice is provided.Phonon transport in two-dimensional carbon materials is investigated from the most essential perspective.