Figure5

Figure 5. Structure of the lowest-energy reconstruction of each surface and relative surface energies of low-energy reconstructions with respect to $$ \Delta \mu _\text{C} $$. (A) and (B) $$ \chi $$-Fe$$ _5 $$C$$ _2 $$(510) surface, (C) and (D) $$ \chi $$-Fe$$ _5 $$C$$ _2 $$(021) surface, (E) and (F) $$ \theta $$-Fe$$ _3 $$C(010) surface. When referring to $$ \chi $$-Fe$$ _5 $$C$$ _2 $$(510) surfaces, "Fe-" or "C-" denotes the Fe-terminated or C-terminated surface, respectively. The numbers in the names of surfaces [e.g., 6-15 in $$ \theta $$-Fe$$ _3 $$C(010) surface] represent the range of column numbers (counted from left to right) from which iron atoms have been removed. The cyan curve in (B) marked by "clean-rec" corresponds to the reconstructed $$ \chi $$-Fe$$ _5 $$C$$ _2 $$(510) surface reported by the previous work of Liu et al.^[24].