First-principles study of light-element doping effects on iron-based superconductors

Nakamura, Hiroki  ; Machida, Masahiko  

Since the discovery of the first iron-based superconductor, various types of iron-based superconductors have been fabricated to attain higher . Recently, it is reported that of an iron-based superconductor LaFeAsOF is enhanced to 35 K by doping hydrogen. These results imply that atoms of light elements, such as hydrogen and oxygen, penetrate into the crystal of iron-based superconductors and transform their structures into more useful ones for superconductivity. In this paper, we investigate how the light elements are doped in the iron-based superconductors by using the first-principles density functional theory. Furthermore, we evaluate the effects of doping on the crystal structures and electronic states and explore the origin of the enhancements.