Native point defects in $T{i}_{3}Ge{C}_2$ and $T{i}_{2}GeC$

Abstract

Using density functional theory, we calculated the formation energy of native point defects (vacancies, interstitials and antisites) in MAX phase $T{i}_{2}GeC$ and $T{i}_{3}Ge{C}_2$ compounds. Ge vacancy with formation energy of 2.87 eV was the most stable defect in $T{i}_{2}GeC$ while C vacancy with formation energy of 2.47 eV was the most stable defect in $T{i}_{3}Ge{C}_2$. Ge vacancies, in particular, were found to be strong phonon scattering centres that reduce the lattice contribution to thermal conductivity in $T{i}_{2}GeC$. In both compounds, the reported high thermal and electrical conductivity is attributed to the electronic contribution that originates from the high density of states at the Fermi level.

arXiv comment7 Pages, 4 Figures, 2 Tables

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