Decompression-driven superconductivity enhancement in In_2Se_3

With the support by the National Natural Science Foundation of China,a collaborative study by the research groups led by Prof.Gao Chunxiao(高春晓)from the State Key Laboratory for Superhard Materials,Institute of Atomic and Molecular Physics,Jilin University and Prof.Chen Bin from the

Revisiting the Electron-Doped SmFeAsO:Enhanced Superconductivity up to 58.6 K by Th and F Codoping

In the iron-based high-To bulk superconductors, Tc above 50 K was only observed in the electron-doped 1111-type compounds. Here we revisit the electron-doped SmFeAsO polycrystals to make a further investigation for the highest Tc in these materials. To introduce more electron carriers and less crystal lattice distortions, we study the Th and F eodoping effects into the Sm-O layers with heavy electron doping. Dozens of Sm1-xThx FeAsO1-yFy samples are synthesized through the solid state reaction method, and these samples are carefully characterized by the structural, resistive, and magnetic measurements. We find that the codoping of Th and F clearly enhances the superconducting Tc more than the Th or F single-doped samples, with the highest record Tc up to 58.6K when x = 0.2 and y=0.225. Further element doping causes more impurities and lattice distortions in the samples with a weakened superconductivity.

High-T_c superconductivity in FeSe at high pressure:Dominant hole carriers and enhanced spin fluctuations

With the support by the National Natural Science Foundation of China and the Ministry of Science and Technology of China,a collaborative study led by Prof.Cheng Jinguang(程金光)from the Institute of Physics,Chinese Academy of Sciences found evidence for the presence of hole pockets and the enhanced spin fluctuations in the pressure-induced high-Tcsuperconductivity phase of FeSe,which was published

Obtaining tetragonal FeAs layer and superconducting K_(x)Fe_(2)As_(2)by molecular beam epitaxy

Atomic characterization on tetragonal FeAs layer and engineering FeAs superlattices is highly desirable to get deep insight into the multi-band superconductivity in iron-pnictides.We fabricate the tetragonal FeAs layer by topotactic reaction of FeTe films with arsenic and then obtain KxFe_(2)As_(2)upon potassium intercalation using molecular beam epitaxy.The in-situ low-temperature√2×√2scanning tunneling microscopy/spectroscopy investigations demonstrate characteristic reconstruction of the FeAs layer and stripe pattern of KxFe_(2)As_(2),accompanied by the development of a superconducting-like gap.The ex-situ transport measurement with FeTe capping layers shows a superconducting transition with an onset temperature of 10 K.This work provides a promising way to characterize the FeAs layer directly and explore rich emergent physics with epitaxial superlattice design.