Observation of unreconstructed square atomic square lattice in Ca(Fe0.965Co0.035)2As2 cleaved at very low temperatures

27th International Conference on Low Temperature Physics

Fente, A.^1 ; Guillamón, I.^1,2 ; Ran, S.^3 ; Vieira, S.^1,2 ; Suderow, H.^1,2 ; Bud'Ko, S.L.^3 ; Canfield, P.C.^3

Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Madrid

E-28049, Spain^1

Unidad Asociada de Bajas Temperaturas y Altos Campos Magnéticos, UAM, CSIC, Cantoblanco, Madrid

E-28049, Spain^2

Ames Laboratory, Department of Physics and Astronomy, Iowa State University, Ames

IA

50011, United States^3

关键词: Layered superconductor;    Liquid helium temperature;    Low temperatures;    Scanning windows;    Surface termination;    Tetragonal crystals;    Topographic images;    Very low temperatures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/2/022046/pdf
DOI  :  10.1088/1742-6596/568/2/022046

来源: IOP

【 摘 要 】

Scanning tunneling microscopy (STM) has been by now made in many pnictide layered superconductors. In AFe2As2(A=Ca, Sr, Ba), surface reconstructions dominate The STM topographic images and no surface termination with The bulk atomic lattice has been reported. Here, we present STM measurements on The surface of Ca(Fe0.965Co0.035)2As2cleaved in-situ below liquid helium temperatures. We observe The ubiquitous surface reconstruction consisting of 1D stripes that can adopt two degenerate orientations with respect to The crystal lattice. By searching over many different scanning windows, we find that low temperature cleaving also exposes surfaces showing The As unreconstructed lattice of The bulk tetragonal crystal, over areas of some tens of nm lateral size.