Superconductivity is observed in AFe2As2 (A = Cs, Rb, K) at temperatures below 4 K. The metastable compound NaFe2As 2 displays superconductivity with a high Tc=25K. These compounds are considered to be strongly hole-overdoped. The stoichiometric LiFeAs is superconducting below 18 K. The origin of superconductivity in LiFeAs is critically investigated and we show that Li deficiency cannot explain the experimental results. We propose that superconducting LiFeAs is stoichiometric and it is equivalent to the high-pressure state of other undoped iron pnictides.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering