Electron-phonon scattering limited intrinsic electrical conductivity of metallic MXenes X₂C (X= Ti or Mo)

The electron-phonon (e-p) scattering mechanism in two metallic MXenes (Ti2C and Mo2C) are investigated using the advanced Wannier-Fourier interpolation scheme. It is found that for both MXenes, the strongly interacting phonons with electrons are mainly attributed to the transverse and longitudinal optical modes (TO + LO). Among acoustic phonon branches, longitudinal acoustic mode exhibits higher coupling strength than either flexural mode or transverse mode. The predicted total e-p coupling of Ti2C (0.280) is smaller than that of Mo2C (0.926). The e-p coupling mechanism in Ti2C or Mo2C is different from graphene, but similar to that of transition-metal dichalcogenides. For the electronic band dispersion most adjacent to Fermi level, we predict the mean electron linewidths of 16.4 meV for Ti2C and 14.3 meV for Mo2C. Using the Ziman formula, the electrical conductivities of Ti2C and Mo2C at 300 K are found to be 5.497 × 104 S cm-1 for Ti2C and 1.593 × 104 S cm-1 for Mo2C with the associated relaxation times 90 fs and 185 fs, respectively. Our calculations indicate that the overall electrical conductivity is determined by both of the e-p coupling and electron concentration in metallic MXenes.