SPP 1458:  High Temperature Superconductivity in Iron Pnictides

• Subject Area: Physics ; Chemistry ; Materials Science and Engineering
• Term: from 2010 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 130149406

The discovery of high temperature superconductivity in FeAs-compounds has attracted worldwide attraction and triggered an enormous amount of research activities in both, solid state physics and solid state chemistry. This interest is due to (1) the large transition temperatures up to 55 K, (2) the very rich physical properties, which exhibit an interesting interplay between crystal structure, magnetism and superconductivity, (3) the large diversity of materials in this new class of high temperature superconductors, and (4) the potential of technical applications of these intermetallic compounds.
It is the intention of this Priority Programme to study “materials and mechanisms” of FeAs high temperature superconductivity. With a systematic materials study it is aimed to synthesise high quality samples of known materials as well as to search for new superconducting compositions. With a combination of experimental and theoretical investigations it is planned to study the basic physical properties of the pnictides and, in particular, to explore the mechanism of this new class of high temperature superconductors.
An important aspect of this research initiative will be the close interdisciplinary collaboration between chemists and physicists, or, in other words, the interaction between materials optimisation and fundamental research. The groups working in chemistry and/or materials science will establish new systems and will optimise the sample quality. The thorough characterisation of the physical properties as well as the theoretical modelling performed by groups working in theoretical and/or experimental physics will not only give insights to the fundamental properties of the pnictides, but will, in addition, give important suggestions to the optimisation and new directions in the synthesis work.

• DFG Programme: Priority Programmes
• International Connection: Austria, Switzerland

Projects

• Ab initio modelling of structural and magnetic phase transitions under pressure and doping for the iron based superconductors (Applicant Valenti, Maria Roser )
• Anisotropy and Magnetism in the EuFe2As2 Family (Applicant Dressel, Martin )
• ARPES of iron-based superconductors (Applicant Borisenko, Sergey )
• C-axis transport of pnictide superconductors (Applicant Müller, Paul )
• Chemical Modification of High-Temperature Superconducting Iron Pnictides: New Chemical Compounds and Characterization (Applicant Niewa, Rainer )
• Coordination and Workshops - High Temperature Superconductivity in Iron Pnictides (Applicant Büchner, Bernd )
• Crystal structure, phase diagram, electronic, magnetic and superconducting properties of AFe2-xMxAs2 -a joint experimental and theoretical study (Applicant Leithe-Jasper, Andreas )
• Effects of compensating doping or chemical pressure in 122-type superconductors and structure-property relations of superconducting platinum-iron arsenides with layered structures (Applicant Johrendt, Dirk )
• Electron selfenergy in the superconducting pnictides:orbital dependence, anisotropy, temperature dependence and its relation with the phase diagram (Applicant Honerkamp, Carsten )
• Electronic ground states and phase diagrams of Fe-pnictide superconductors (Applicant Klauss, Hans-Henning )
• Electronic, structural, and magnetic properties of single crystalline pnictides: Thermodynamic studies down to ultra-low temperatures (Applicants Enss, Christian Walter Dietrich ;  Klingeler, Rüdiger )
• Electronic structure and ultrafast dynamics of FeAs-based superconductors by angle- and timeresolved photoemission spectroscopy (Applicant Bovensiepen, Uwe )
• Fermi surfaces of iron pnictides investigated by use of magnetic quantum oscillations (Applicant Wosnitza, Joachim )
• Ferromagnetism and Superconductivity in LiFeAs (Applicant Büchner, Bernd )
• High-pressure single crystal growth and characterization of the 1111-type iron-pnictide superconductors and related systems (Applicant Krellner, Cornelius )
• High-Pressure Synthesis and Crystal Growth, Characterization and Thermodynamic Properties of Iron-Pnictide Superconductors and Related Systems (Applicant Lang, Michael )
• High-temperature superconductivity in iron pnictides: syntheses and structural chemistry of transition-metal pnictides and related structures (Applicant Schleid, Thomas )
• In-plane electronic anisotropy of differently doped AFe2As2 (A = Ba, Eu) superconductors (Applicant Gegenwart, Philipp )
• Interplay of structure, magnetism and superconductivity in 122 pnictides: Crystal growth, thermodynamics, and first-principle calculations (Applicant Meingast, Christoph )
• Investigation of low-energy excitations of iron-based superconductors by NMR and transport (Applicant Grafe, Hans-Joachim )
• Investigations in the interplay between magnetism and superconductivity in the iron-pnictides by high-pressure studies (Applicant Nicklas, Michael )
• Itinerant and localized magnetism in Fe based superconductors - Electron Spin Resonance spectroscopy and single crystal growth (Applicant Deisenhofer, Joachim )
• Josephson effects at iron pnictides - phase-sensitive experiments (Applicant Seidel, Paul )
• Magnetic fluctuations and nematic order in iron-based superconductors: Stability, short-time dynamics, transport and orbital correlations (Applicants Eremin, Ilya ;  Schmalian, Jörg )
• Magneto-elastic couplings and superconductivity in 11-type chalcogenides: Thermal and quantum fluctuations (Applicant Schwarz, Ulrich )
• Magnetoelastic properties of Fe superconductors via ab-initio DFT calculations (Applicant Boeri, Lilia )
• Neutron scattering investigation of iron pnictides superconductors (Applicant Prokes, Karel )
• Neutron-scattering studies on magnetic correlations in FeAs-based superconductors (Applicant Braden, Markus )
• Novel and metastable arsenic free Fe based pnictide superconductors synthesized by reactive molecular beam epitaxy (Applicant Alff, Lambert )
• Phase sensitive tests on Fe-based superconductors exploiting novel designs (Applicant Haindl, Silvia )
• Preparation and crystal growth of superconducting and magnetic rare earth-transition metal oxypnictides and alkali / earth alkali iron arsenides (Applicant Büchner, Bernd )
• Raman study of the interrelation of electron dynamics and phase transitions iron-based compounds (Applicant Hackl, Rudolf )
• Scanning Tunneling Spectoscopy of Iron Pnictides (Applicant Hemker-Heß, Christian )
• Spectroscopy of local excitations in iron pncictide superconductors (Applicant Wahl, Peter )
• Spin and charge dynamics in iron-based superconductors: A complementary neutron scattering and spectroscopic ellipsometry study (Applicant Inosov, Dmytro )
• Spin-density wave in pnictides: Excitonic instability, dynamics, and transport (Applicant Timm, Carsten )
• Superconductivity and nematic phases in iron pnictides from LDA+Gutzwiller theory (Applicants Boeri, Lilia ;  Gebhard, Florian )
• Synthesis and crystal growth of new and well-established iron pnictide superconductors (Applicant Büchner, Bernd )
• Synthesis, structure, and properties of selected ZrCuSiAs type pnictide oxides and related compounds (Applicant Pöttgen, Rainer )
• Thermodynamic and Transport Properties of Iron-Pnictide Superconductors under hydrostatic (Hegas) pressure (Applicant Lang, Michael )
• Towards a realistic description of the interplay of bosonic and fermionic degrees of freedom in the physical properties of Fe pnictide in the normal and superconducting state: multiband approaches with the account of disorder effects (Applicants van den Brink, Jeroen ;  Drechsler, Ph.D., Stefan-Ludwig ;  Efremov, Dmitri )
• Transport measurements, structure and Mössbauer investigations of FeSe-related novel superconductors under high pressure up to 100GPa (Applicants Ksenofontov, Vadim ;  Medvediev, Sergiy )
• Unconventional quantum states of matter in Fe-based superconductors (Applicant Hanke, Werner )
• Variation of FeAs-superconductors through replacement of As by Si or Ge and Fe by Co or Ni (Applicant Hlukhyy, Viktor )

• Spokesperson: Professor Dr. Bernd Büchner
• Deputies: Professor Dr. Rudolf Hackl; Professor Dr. Carsten Honerkamp; Professor Dr. Dirk Johrendt
• Participating Persons: Professor Dr. Lambert Alff; Professorin Dr. Lilia Boeri; Professor Dr. Uwe Bovensiepen; Professor Dr. Jeroen van den Brink; Professorin Dr. Maria Daghofer; Dr. Joachim Deisenhofer; Stefan-Ludwig Drechsler, Ph.D.; Professor Dr. Martin Dressel; Dr. Dmitri Efremov; Professor Dr. Florian Gebhard; Professor Dr. Philipp Gegenwart; Dr. Hans-Joachim Grafe; Dr. Silvia Haindl; Dr. Viktor Hlukhyy; Dr. Jens Hänisch; Dr. Ruben Hühne; Professor Dr. Dmytro Inosov; Professor Dr. Rüdiger Klingeler; Professor Dr. Michael Koblischka; Professor Dr. Cornelius Krellner; Dr. Vadim Ksenofontov; Professor Dr. Michael Lang; Dr. Andreas Leithe-Jasper; Dr. Sergiy Medvediev; Dr. Christoph Meingast; Dr. Karel Prokes; Dr. Helge Rosner; Professor Dr. Thomas Schleid; Professor Dr. Jörg Schmalian; Privatdozent Dr. Ulrich Schwarz; Professor Dr. Paul Seidel; Professor Dr. Carsten Timm; Professor Dr. Peter Wahl; Dr. Thomas Wolf; Dr. Yinguo Xiao; Dr. Sergei Zherlitsyn