title: Anisotropic intrinsic lattice thermal conductivity of borophane from first-principles calculations.
abstract: Borophene (boron sheet) as a new type of two-dimensional (2D) material was grown successfully recently. Unfortunately, the structural stability of freestanding borophene is still an open issue. Theoretical research has found that full hydrogenation can remove such instability, and the product is called borophane. In this paper, using first-principles calculations we investigate the lattice dynamics and thermal transport properties of borophane. The intrinsic lattice thermal conductivity and the relaxation time of borophane are investigated by solving the phonon Boltzmann transport equation (BTE) based on first-principles calculations. We find that the intrinsic lattice thermal conductivity of borophane is anisotropic, as the higher value (along the zigzag direction) is about two times of the lower one (along the armchair direction). The contributions of phonon branches to the lattice thermal conductivities along different directions are evaluated. It is found that both the anisotropy of thermal conductivity and the different phonon branches which dominate the thermal transport along different directions are decided by the group velocity and the relaxation time of phonons with very low frequency. In addition, the size dependence of thermal conductivity is investigated using cumulative thermal conductivity. The underlying physical mechanisms of these unique properties are also discussed in this paper.
authors.affiliation: School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471023, China. ganglew@163.com.
authors.forename: Gang
authors.identifier: http://orcid.org/0000-0001-9033-7376
authors.initials: G
authors.lastname: Liu
authors.affiliation: Department of Physics, College of Science, Shihezi University, Xinjiang 832003, China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Physics, College of Science, Shihezi University, Xinjiang 832003, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471023, China. ganglew@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang