Abstract
Charge doping of iron-pnictide superconductors leads to collective pinning of flux vortices, whereas isovalent doping does not. Moreover, flux pinning in the charge-doped compounds is consistently described by the mean-free path fluctuations introduced by the dopant atoms, allowing for the extraction of the elastic quasiparticle scattering rate. The absence of scattering by dopant atoms in isovalently doped is consistent with the observation of a linear temperature dependence of the low-temperature penetration depth in this material.
- Received 12 May 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.267002
© 2010 The American Physical Society