Fermiology of two-dimensional titanium carbide and nitride MXenes

Mohammad Bagheri, Rina Ibragimova, Hannu Pekka Komsa

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)
275 Downloads (Pure)

Abstract

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

Original languageEnglish
Article number035408
Number of pages7
JournalPhysical Review B
Volume104
Issue number3
DOIs
Publication statusPublished - 7 Jul 2021
MoE publication typeA1 Journal article-refereed

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