  Compounds from groups IV and V have been the focus of recent research due to
their impressive physical characteristics and structural stability. In this
study, the MX monolayers (M=Sn, Pb; N=P, As) are investigated with
first-principles calculations based on Boltzmann transport theory. The results
show that SnP, SnAs, and PbAs all exhibit indirect band gaps, whereas PbP is
the only semiconductor with a direct band gap. One important finding is that
intravalley scattering has a significant impact on electron-phonon coupling.
Interestingly, changes in carrier concentration do not affect the electron
mobility within these MX monolayers, with SnP exhibiting the highest electron
mobility among them. Subsequently, the SnP under a 6% biaxial strain is further
explored and the results demonstrated a considerable increase in electron
mobility to 2,511.9 cm^2/Vs, which is attributable to decreased scattering.
This suggests that MX monolayers, especially SnP, are promising options for 2D
semiconductor materials in the future.
