Formation of dysprosium carbide on the graphite (0001) surface

作者：Lii-Rosales, Ann; Zhou, Yinghui; Wallingford, Mark; Wang, Cai-Zhuang; Tringides, Michael C.; Thiel, P. A.^*

来源：Physical Review Materials, 2017, 1(2): 026002.

DOI：10.1103/PhysRevMaterials.1.026002

• INTERCALATION COMPOUNDS
• GRAPHENE

Using scanning tunneling microscopy, we characterize a surface carbide that forms when Dy is deposited on the basal plane of graphite. To form carbide islands on terraces, Dy is first deposited at 650-800 K, which forms large metallic islands. Upon annealing at 1000 K, these clusters convert to carbide. Deposition directly at 1000 K is ineffective because nucleation on terraces is inhibited. Reaction is signaled by the fact that each carbide cluster is partially or totally surrounded by an etch pit. The etch pit is one carbon layer deep for most carbide clusters. Carbide clusters are also identifiable by striations on their surfaces. Based on mass balance, and assuming that only the surface layer of carbon is involved in the reaction, the carbide has stoichiometry Dy2C. This is Dy-rich compared with the most common bulk carbide DyC2, which may reflect limited surface carbon transport to the carbide.

• 出版日期2017-7-12
• 单位厦门大学