Format

Send to

Choose Destination
Phys Rev Lett. 2009 Mar 6;102(9):097002. Epub 2009 Mar 3.

Scanning tunneling spectroscopy and vortex imaging in the iron pnictide superconductor BaFe1.8Co0.2As2.

Author information

1
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

Abstract

We present an atomic resolution scanning tunneling spectroscopy study of superconducting BaFe1.8Co0.2As2 single crystals in magnetic fields up to 9 T. At zero field, a single gap with coherence peaks at Delta=6.25 meV is observed in the density of states. At 9 and 6 T, we image a disordered vortex lattice, consistent with isotropic, single flux quantum vortices. Vortex locations are uncorrelated with strong-scattering surface impurities, demonstrating bulk pinning. The vortex-induced subgap density of states fits an exponential decay from the vortex center, from which we extract a coherence length xi=27.6+/-2.9 A, corresponding to an upper critical field Hc2=43 T.

Supplemental Content

Full text links

Icon for American Physical Society
Loading ...
Support Center