| Author | Li, G., et al. |
|---|---|
| Title | Role of Antiferromagnetic Ordering in the (1 x 2) Surface Reconstruction of Ca(Fe1-xCox)(2)As-2 |
| Year | 2014 |
| Journal | Physical Review Letters |
| Abstract | Low energy electron diffraction, scanning tunneling microscopy and spectroscopy, and first-principles spin-dependent density functional theory are utilized to investigate the geometric, electronic, and magnetic structures of the stripe-ordered (1×2) surface of Ca(Fe1−xCox)2As2 (x=0, 0.075). The surface is terminated with a 50% Ca layer. Compared to the bulk, the surface Ca layer has a large inward relaxation (∼0.5 Å), and the underneath As−Fe2−As layer displays a significant buckling. First-principles calculations show that the (1×2) phase is stabilized by the bulk antiferromagnetic spin ordering through the spin-charge-lattice coupling. Strikingly, a superconducting gap (∼7 meV at 7.4 K) is observed to spatially coexist with the (1×2) phase (x=0.075 compound). This implies the coexistence of both superconductivity and AFM ordering at the surface. |
| DOI Link | 10.1103/PhysRevLett.112.077205 |