Study of the Structural Phase Transition in Diamond (100) & (111) Surfaces

Abstract Diamond is an insulating material in the bulk form, but exhibits conducting characteristics when its surface is functionalized. Understanding the electronic and physical properties of diamond surfaces is important for their successful implementation in high-power, high-frequency device applications. Density-functional theory (DFT) coupled with the AutoNEB method is used here to investigate the effect of reconstruction mechanisms on the electronic and structural properties of C(111) and C(100) surfaces. C(100) exhibits an exothermic reaction during reconstruction with no observable intermediates or transition states. The observed energy difference between the bulk-like and reconstructed phases is -0.16 eV/atom. For C(111), a new intermediate state is predicted between the bulk-like and fully reconstructed Pandey chain surfaces, with a per atom energy difference of -0.01 eV from the bulk-like 2 × 1 surface. Furthermore, an analysis into the electronic properties of both reconstructed phases reveals an electronic phase transformation. For the C(100) phase, we observed a metallic-to-semiconductor electronic phase transition. In contrast, the C(111) phase exhibited a metallic to semi-metallic electronic phase transformation. Our findings establish a fundamental understanding of the phase transition mechanisms in these surfaces and highlight a need for a tailored and sophisticated surface dependent preparation and fabrication approach during device design.