Fermiology of two-dimensional titanium carbide and nitride MXenes

MXenes are a family two-dimensional transition-metal carbide and nitride materials, which often exhibit very good metallic conductivity thus of great interest for applications in, e.g., flexible electronics, electrocatalysis, electromagnetic interference shielding. However, surprisingly little is known about the fermiology MXenes, i.e., shape size their Fermi surfaces, its effect on material properties. One reason this may be that MXene surfaces almost always covered by mixture functional groups, studying disordered systems cumbersome. Here, we study four common Ti-based as function surface group composition. We first calculate effective band structures with explicit mixed observe gradual evolution in filling Ti-d resulting shift level. then demonstrate these can closely approximated using pseudohydrogenated also compare favorably to experimental angle-resolved photoemission spectroscopy results. By modifying pseudohydrogen charge proceed plot all extract properties, such Fermi-surface area average velocity. These turn used evaluate electrical relaxation time fitted experimentally measured conductivities.