First-principles prediction of the lattice thermal conductivity of two-dimensional (2D) h-BX (X = P, As, Sb) considering the effects of fourth-order and all-order scattering

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.

Strain-Driven High Thermal Conductivity in Hexagonal Boron Phosphide Monolayer

“…The h-BP monolayer belongs to the hexagonal honeycomb structure, which shows the same periodicity of lattice structure along the a direction and b direction, as shown in Figure . The lattice parameter ( a = b ) and <B– P > bond length of the h-BP monolayer are 3.21 and 1.85 Å without strain, respectively, which are in good agreement with the previous theoretical prediction of 3.21 and 1.86 Å. , See Table for a more detailed comparison of related parameters for h-BX monolayers. In this work, tensile strains of 0, 2, 4, 6, and 8% were applied to tune the thermal transport properties of the h-BP monolayer by varying the lattice constants a and b simultaneously.…”

“…Recently, the hexagonal binary group boron–VA monolayers (h-BX, XN, P, As, and Sb) have been found to exhibit relatively higher κ l values than other graphenelike materials, i.e., the κ l values of h-BX monolayers are about 100–1000 W/mK at 300 K, respectively. ,, Besides, the h-BX monolayers also show excellent electron, magnetic, optical, and other properties. − Especially, the direct band gap semiconductor h-BP monolayer (its lattice structure is given in Figure ) possesses a hole mobility of 1.37–2.61 × 10 4 cm 2 /(V s) and an electron mobility of 5.00–6.88 × 10 4 cm 2 /(V s), which are remarkably higher than those of many graphenelike materials, such as phosphorene and MoS 2 monolayer . Simultaneously, this monolayer exhibits a robust optical absorption from 1.4 to 4.0 eV .…”

Soft phonon modes lead to suppressed thermal conductivity in Ag-based chalcopyrites under high pressure

“…It should be noted that our calculations only include threephonon scattering, although four-phonon and even higherorder scattering have been investigated and applied to many semiconductors, [32][33][34][35][36] and the discrepancy in thermal conductivity between the three-phonon scattering theory and the experimental values has been well explained by incorporating higher-order scattering. However, it is well known that the calculation of the fourth-order force constants and the solving of phonon BTE with four-phonon scattering are proved to be a very time-and resource-consuming task.…”

The electron–phonon scattering and charge transport of the two-dimensional (2D) polar h-BX(X = P, As, Sb) monolayers

“…It is well known that carrier mobility is used to characterize how fast carriers (electrons/holes) can move under the influence of an electric field. Generally, a high carrier mobility is more desirable in practical applications because it determines the switching frequency in transistors, the photoconductive gain in photodetectors, as well as the transport properties in solar cells and light-emitting devices [4,[7][8][9][10]. To our knowledge, the WS 2 and MoS 2 monolayers have a room-temperature carrier mobility of ∼200 cm 2 V −1 s −1 [11].…”

“…With the rapid development of the semiconductor industry and the sustained scaling of transistors according to Moore's law [1], the search for high-performance semiconductor materials has become a pressing task for scientific researchers. In recent years, two-dimensional (2D) materials have attracted considerable interest owing to their outstanding photoelectric properties and ultrathin features [2][3][4]. Recently, Wu et al have successfully prepared an ultra-small MoS 2 transistor with a vertical structure, achieving an effective gate length of 0.34 nm for the first time [5].…”