# Nanoscale Surface Element Identification and Dopant Homogeneity in the High-$$T_c$$ Superconductor $$Pr_xC_{1-x}Fe_2As_2$$

 Title: Nanoscale Surface Element Identification and Dopant Homogeneity in the High-$$T_c$$ Superconductor $$Pr_xC_{1-x}Fe_2As_2$$ Author: Zeljkovic, Ilija; Huang, Dennis; Song, Can-Li; Lv, Bing; Chu, Ching-Wu; Hoffman, Jenny Eve Note: Order does not necessarily reflect citation order of authors. Citation: Zeljkovic, Ilija, Dennis Huang, Can-Li Song, Bing Lv, Ching-Wu Chu, and Jennifer E Hoffman. 2013. Nanoscale surface element identification and dopant homogeneity in the High-$$T_c$$ Superconductor Pr$$_x$$Ca$$_{1-x}Fe_2As_2$$. Physical Review B 87:201108. Full Text & Related Files: PrCa122.pdf (4.033Mb; PDF) Abstract: We use scanning tunneling microscopy to determine the surface structure and dopant distribution in $$Pr_xCa_{1-x}Fe_2As_2$$, the highest-$$T_c$$ member of the 122 family of iron-based superconductors. We identify the cleaved surface termination by mapping the local tunneling barrier height, related to the work function. We image the individual Pr dopants responsible for superconductivity, and show that they do not cluster, but in fact repel each other at short length scales. We therefore suggest that the low volume fraction high-$$T_c$$ superconducting phase is unlikely to originate from Pr inhomogeneity. Published Version: doi:10.1103/PhysRevB.87.201108 Other Sources: http://arxiv.org/abs/1301.4942 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:10735563 Downloads of this work: