The carrier mobility and superconducting properties of monolayer oxygen-terminated functionalized MXene Ti ₂ CO ₂

In this study, the carrier mobility of monolayer Ti₂CO₂ was evaluated by employing the Boltzmann transport equation and superconducting transition temperature (T_c) of Ti₂CO₂ was determined by utilizing the Migdal and Eliashberg formalism in the first-principles framework. In contrast to previous studies, the results reveal that optical phonons in monolayer Ti₂CO₂ have dominant roles in scattering processes, which significantly reduce the mobility of carriers. Alongside the rigid band model, the jellium model is implemented to investigate the screening effects on electron-phonon interactions. Based on the jellium model and full-band electron-phonon calculations, the predicted maximum electron mobility at room temperature is 38 cm² V^-1 s^-1 in which 80% of the total scattering rate originates from the intra-valley transitions within the M-valleys, indicating the crucial role of the long wavelength phonon wavevectors in scattering processes. On the other hand, for the p-type material, a maximum room temperature mobility of about 285 cm² V^-1 s^-1 is calculated, which can be explained by a relatively small effective mass and tiny scattering phase space. Moreover, a maximum T_c of 39 (10) K is obtained for the n-type monolayer Ti₂CO₂ based on the rigid (jellium) model. Outcomes indicate that the important peaks of α²F(ω) are mainly caused by the optical phonons. The remarkable couplings between the electron states and phonons are related to the non-zero slope of (near the Brillouin zone center) the longitudinal optical branch denoted by E_u caused by the displacements of oxygen and carbon atoms at intermediate and high energy ranges of phonon dispersion, respectively.