Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 110: Superconductivity: Fe-based Superconductors - 1111 and Others

TT 110.3: Vortrag

Freitag, 16. März 2018, 10:00–10:15, H 3010

Interplay between electronic order and superconductivity in pnictides: The case of NdFeAs(OF) — •Mahmoud Abdel-Hafiez¹, H. K. Mao², Masaki Mito³, Agnes Adamski¹ und Cornelius Krellner¹ — ¹Institute of Physics, Goethe University Frankfurt, 60438 Frankfurt/M, Germany — ²Center for High Pressure Science and Technology Advanced Research, Shanghai, 201203, China — ³Graduate School of Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550, Japan

One of the crucial issues to elucidate the mechanism leading to high-temperature superconductivity is the nature of pairing, e.g., the symmetry and structure of the superconducting order parameter. Recently, we have reported on the superconducting gap in the newly synthesized single crystals of F-doped NdFeAsO. Our observations clearly show that the superconducting energy gap is nodeless. Additionally, pressure has long been recognized as a versatile tuning parameter which can sensitively change the electron correlations in materials. Through an extensive transport study under high-pressure up to 50 GPa, we have clarified in bulk NdFeAs(OF) the competition between ferromagnetism (FM) and superconductivity, where FM is induced by the 4f moments of Nd upon compression. We construct a comprehensive pressure-temperature phase diagram which shows a crossover from Fermi-liquid to non-Fermi-liquid to Fermi-liquid (FL-NFL-FL) alongside a monotonic suppression of the superconductivity with increasing the pressure, before the FM appears at pressures above.