Insights into the Fracture Nature of Hematite from First Principles DFT Calculations.

Hematite, as an important iron source, usually crystallizes in the structure of rhombohedral R3̅c in nature. To date, reports on the major exposed surface of hematite are still inconclusive. Herein, the fracture nature of hematite is studied by the density functional theory (DFT) method. The fracture surface morphology analysis predicts the fracture dominance of the (012) plane structurally. Besides, the lowest surface broken bond density ( D b ) and the surface energy among all of the investigated surfaces also establish the exposure priority of the (012) surface. In addition, the (110) and (104) surfaces also show a strong fracture potential. In our proposed partition model, the exposure priority of (110) and (104) surfaces in region 2 with a lower surface energy and surface broken bond density is second only to the (012) surface. The other surfaces, except for the (012), (110), and (104) surfaces, are divided into region 3; here, the exposure of the surfaces located in this region is considered to be uncompetitive.