Polar Optical-Phonon Dominated Electrical Transport in Ti2CO2 MXene

Abstract

Two-dimensional Ti2CO2 MXene is promising for applications in electronics and optoelectronics, where high intrinsic mobility is essential to achieving high performance. Therefore, accurate prediction of carrier mobility is important for these types of materials. Here, we show that full electron–phonon coupling (EPC) calculations can accurately predict the carrier mobility for polar materials like Ti2CO2 MXene. Based on full EPC calculations and mode-by-mode analyses of the phonon-limited carrier transport in Ti2CO2 MXene, we demonstrate that the EPC matrix of optical phonons is significantly higher than that of the acoustic modes, and the carrier scattering process is dominated by the longitudinal optical phonon (Fröhlich interaction). Consequently, the calculated carrier mobility of Ti2CO2 at 300 K is 319.64 cm2/Vs for the hole and 16.69 cm2/Vs for the electron at a carrier concentration of nc = 1 × 1012 cm–2, which are over one order of magnitude lower than that predicted by the deformation potential theory method. The present work demonstrates the importance and necessity of considering the full EPC to accurately predict the carrier mobility of MXenes and other polar materials.