Affiliation:
1. Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024, China
2. Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
Abstract
Recently, cubic boron arsenide (c-BAs) has attracted global attention due to its higher lattice thermal conductivity ([Formula: see text]), which is comparable to diamond, and excellent thermal properties. Can c-BAs achieve the leap in [Formula: see text] after transforming its structure from three-dimensional (3D) to two-dimensional (2D) like diamond to graphene? Previous studies have only investigated the [Formula: see text] considering three-phonon scattering and isotope scattering, and the calculated results are diverse. In this study, we first calculate second-order interatomic force constants (IFCs) and third-order IFCs to iteratively solve the Boltzmann transport equation (BTE) and to obtain the [Formula: see text] of monolayer hexagonal BX (X = P, As, Sb), h-BX (X = P, As, Sb), considering only three-phonon and isotope scattering. The corresponding [Formula: see text] of h-BX are 278.2, 205.7, and 20.2 W/mK at room temperature, and we explain the monotonous change that [Formula: see text] decreases with the increase of average atomic mass ( mavg) different from previous studies. Subsequently we use regular residual analysis (RRA) to determine the necessity of including four-phonon scattering when calculating the [Formula: see text] of monolayer h-BX. By calculating the fourth-order IFCs, we obtain the [Formula: see text] of monolayer h-BX including four-phonon scattering. The values of [Formula: see text] at room temperature are 61.12, 37.99, and 5.73 W/mK, which are highly consistent with the [Formula: see text] of monolayer h-BX as predicted by the phonon spectral energy density (SED) method. The phonon SED method considers all-order scattering and gives values of 54.05 ± 21.48 W/mK (h-BP), 18.20 ± 4.47 W/mK (h-BAs), and 2.46 ± 0.34 W/mK (h-BSb), respectively. Our results show that the influence of four-phonon scattering on the [Formula: see text] of monolayer h-BX is significant, and the [Formula: see text] and [Formula: see text] still undergo monotonic changes after including four-phonon scattering. The main factors that determine the low (ultra-low) [Formula: see text] of monolayer h-BAs (h-BSb) are large mavg and weaker bonding strength, the existence of intermediate frequency ZO and scattered acoustic branches, the strong anharmonicity caused by the in-plane vibrations of As (Sb) atoms, and four-phonon scattering. This study aims to end the variance within monolayer h-BAs [Formula: see text] numerical simulation and demonstrate the potential of monolayer h-BSb in thermoelectric field applications.
Funder
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities
Subject
General Physics and Astronomy
Cited by
10 articles.
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