Lower lattice thermal conductivity in SbAs than As or Sb monolayers: a first-principles study

Abstract

Phonon transport in group-VA element (As, Sb and Bi) monolayer semiconductors has been widely investigated in theory, and, of them, monolayer Sb (antimonene) has recently been synthesized. In this work, phonon transport in monolayer SbAs is investigated with a combination of first-principles calculations and the linearized phonon Boltzmann equation. It is found that the lattice thermal conductivity of monolayer SbAs is lower than those of both monolayer As and Sb, and the corresponding sheet thermal conductance is 28.8 W K at room temperature. To understand the lower lattice thermal conductivity in monolayer SbAs than those in monolayer As and Sb, the group velocities and phonon lifetimes of monolayer As, SbAs and Sb are calculated. The calculated results show that the group velocities of monolayer SbAs are between those of monolayer As and Sb, but that the phonon lifetimes of SbAs are smaller than those of both monolayer As and Sb. Hence, the low lattice thermal conductivity in monolayer SbAs is attributed to very small phonon lifetimes. Unexpectedly, the ZA branch has very little contribution to the total thermal conductivity, only 2.4%, which is obviously different from those of monolayer As and Sb with very large contributions. This can be explained by very small phonon lifetimes for the ZA branch of monolayer SbAs. The lower lattice thermal conductivity of monolayer SbAs compared to that of monolayer As or Sb can be understood by the alloying of As (Sb) with Sb (As), which should introduce phonon point defect scattering. We also consider the isotope and size effects on the lattice thermal conductivity. It is found that isotope scattering produces a neglectful effect, and the lattice thermal conductivity with a characteristic length smaller than 30 nm can reach a decrease of about 47%. These results may offer perspectives on tuning the lattice thermal conductivity by the mixture of multiple elements for applications of thermal management and thermoelectricity, and motivate further experimental efforts to synthesize monolayer SbAs.

Prediction of hydrogenated group IV–V hexagonal binary monolayers

“…Based on these maxima, the Debye temperatures are obtained by θ D = hν m /K B 47 , where h and K B are the Planck and Boltzmann constants, respectively. The calculated temperatures are in the range of 143 to 54 K (listed in Table 1) which are lower than graphene (2266 K), silicene (798 K), phosphorene (206 K), arsenene (170 K), and comparable to antimonene (101 K), bismuthene (50 K), and stanene (72 K) [47][48][49][50] . Such low Debye temperatures and large buckling heights, which are indicatives of low lattice thermal conductivity, may bring hope for these monolayers to be suitable candidates for thermoelectric applications.…”

“…Also, it is clear that the maxima of acoustic modes decline with going down in group IV and V where and display the highest (100 ) and lowest (38 ) peaks. Based on these maxima, the Debye temperatures are obtained by 47 , where h and are the Planck and Boltzmann constants, respectively. The calculated temperatures are in the range of 143 to 54 K (listed in Table 1 ) which are lower than graphene (2266 K), silicene (798 K), phosphorene (206 K), arsenene (170 K), and comparable to antimonene (101 K), bismuthene (50 K), and stanene (72 K) 47 – 50 .…”

Effects of low dimensionality on electronic structure and thermoelectric properties of bismuth

“…It should be noted that the inuence of the phonon group velocity and phonon lifetime on the lattice thermal conductivity from the present study match well with similar theoretical conclusions about the 2D V monolayer family in the literature. 18,49…”

Thermoelectric effect and devices on IVA and VA Xenes

“…200 Other 2D binary materials composed of Group IVA and VA elements have also been theoretically investigated, such as exfoliated black As-P fabricated in back-gate FET, SbAs with low lattice thermal conductivity and other IV-V or V-V binary materials. 38,[204][205][206][207][208][209][210] IVA or VA based chalcogenides and oxides have been studied too. TIs, such as Bi 2 Te 3 , Bi 2 Se 3 and their alloys are best-candidate thermoelectric bulk materials near room temperature.…”