The conflicting role of buckled structure in phonon transport of 2D group-IV and group-V materials

Abstract

Controlling heat transport through material design is one important step toward thermal management in 2D materials. To control heat transport, a comprehensive understanding of how structure influences heat transport is required. It has been argued that a buckled structure is able to suppress heat transport by increasing the flexural phonon scattering. Using a first principles approach, we calculate the lattice thermal conductivity of 2D mono-elemental materials with a buckled structure. Somewhat counterintuitively, we find that although 2D group-V materials have a larger mass and higher buckling height than their group-IV counterparts, the calculated κ of blue phosphorene (106.6 W mK) is nearly four times higher than that of silicene (28.3 W mK), while arsenene (37.8 W mK) is more than fifteen times higher than germanene (2.4 W mK). We report for the first time that a buckled structure has three conflicting effects: (i) increasing the Debye temperature by increasing the overlap of the p orbitals, (ii) suppressing the acoustic-optical scattering by forming an acoustic-optical gap, and (iii) increasing the flexural phonon scattering. The former two, corresponding to the harmonic phonon part, tend to enhance κ, while the last one, corresponding to the anharmonic part, suppresses it. This relationship between the buckled structure and phonon behaviour provides insight into how to control heat transport in 2D materials.

2D Crystal–Based Fibers: Status and Challenges

“…This significant development arouses great enthusiasm in fundamental research of physics. In the sense of application value, when bulk materials are transformed into corresponding 2D crystals, their properties will be greatly improved, and some new properties will be obtained, for example, quantum Hall effect, excellent optical properties, high specific surface area, ultrahigh carrier mobility at room temperature, and high thermal conductivity . Therefore, 2D crystals have attracted extensive attention of researchers in the fields of optoelectronic devices, energy materials, catalysts, and biomaterials, once graphene has been successfully prepared.…”

Arsenene and Antimonene: Two-Dimensional Materials with High Thermoelectric Figures of Merit

“…[36], and systematic insight into the interrelation between buckling and transport in two-dimensional group-IV and group-V materials was given in Ref. [37]. However, the thermoelectric properties of arsenene and antimonene have escaped attention.…”

Theoretical studies on tunable electronic structures and potential applications of two‐dimensional arsenene‐based materials

“…Note that instead of using conductivity quantities, conductance quantities are applied to describe thermoelectric properties of nanomaterials and TIs . By using DFT calculations in combination with Boltzmann transport theory, the thermoelectric properties of w ‐arsenene have been investigated …”

“…136 in combination with Boltzmann transport theory, the thermoelectric properties of w-arsenene have been investigated. 130,[143][144][145][146][147][148] The figure of merit at 300 K for phosphorene, arsenene (w-As), and SnS monolayers along zigzag (ZZ) and armchair (AC) direction was systematically studied, as shown in Figure 14b and c. 130 The calculated anisotropic thermal conductivity at room temperature is 30.4 W/mK along the ZZ, larger than that (7.8 W/mK) of AC directions. 143,144 The temperature dependence of ZT max is presented in Figure 13d and e. 130 It was noted that the arsenene exhibited larger ZT values than phosphorene.…”