The cleavage surface of the BaFe_(2-x)Co_(x)As_(2) and Fe_(y)Se_(1-x)Te_(x) superconductors: from diversity to simplicity

Abstract

We elucidate the termination surface of cleaved single crystals of the BaFe_(2-x)Co_(x)As_(2) and Fe_(y)Se_(1-x)Te_(x) families of the high temperature iron based superconductors. By combining scanning tunneling microscopic data with low energy electron diffraction we prove that the termination layer of the Ba122 systems is a remnant of the Ba layer, which exhibits a complex diversity of ordered and disordered structures. The observed surface topographies and their accompanying superstructure reflections in electron diffraction depend on the cleavage temperature. In stark contrast, Fe_(y)Se_(1-x)Te_(x) possesses only a single termination structure - that of the tetragonally ordered Se_(1-x)Te_(x) layer.

4 pages, 4 figures

References in corpus (4)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Scanning Tunneling Spectroscopy and Vortex Imaging in the Iron-Pnictide Superconductor BaFe${}_{1.8}$Co${}_{0.2}$As${}_2$
• Nanoscale superconducting gap variations, strong coupling signatures and lack of phase separation in optimally doped BaFe1.86Co0.14As2
• A high resolution, hard X-ray photoemission investigation of BaFe${}_2$As${}_2$: moderate influence of the surface and evidence for a low degree of Fe 3d - As 4p hybridization of the near-E${}_F$ electronic states

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• Imaging atomic-scale effects of high-energy ion irradiation on superconductivity and vortex pinning in Fe(Se,Te)
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• Measurement of a Sign-Changing Two-Gap Superconducting Phase in Electron-Doped Ba(Fe_{1-x}Co_x)_2As_2 Single Crystals using Scanning Tunneling Spectroscopy
• Unexpected weak spatial variation of local density of sates induced by individual Co impurity atoms in Na(Fe{1-x}Cox)As as revealed by scanning tunneling spectroscopy
• Pseudogap-less high T${}_c$ superconductivity in BaCo${}_x$Fe${}_{2-x}$As${}_2$
• ARPES observation of Mn-pnictide hybridization and negligible band structure renormalization in BaMn${}_2$As${}_2$ and BaMn${}_2$Sb${}_2$
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• Evidence for a robust sign-changing s-wave order parameter in monolayer films of superconducting Fe (Se,Te)/Bi2Te3
• Surface adatom conductance filtering in scanning tunneling spectroscopy of Co-doped BaFe2As2 iron pnictide superconductors
• Common ($\pi$,$\pi$) Band Folding and Surface Reconstruction in FeAs-Based Superconductors
• Enhanced Surface Superconductivity in Ba(Fe${}_{0.95}$Co${}_{0.05}$)${}_2$As${}_2$