Direct observation of the influence of the FeAs4 tetrahedron on superconductivity and antiferromagnetic correlations in Sr2VO3FeAs

Gaston Garbarino (1) , Ruben Weht (2) , Amadou Sow , Claudine Lacroix (3) , André Sulpice (4) , Mohamed Mezouar (1) , Xiyu Zhu (5) , Fei Han (5) , Hai Hu Wen (5) , Manuel Nunez-Regueiro (4)

1 ESRF - European Synchrotron Radiation Facility
2 CNEA - Comisión Nacional de Energía Atómica [ARGENTINA]
3 NEEL - TMC - Théorie de la Matière Condensée
4 NEEL - MagSup - Magnétisme et Supraconductivité
5 CAS - Chinese Academy of Sciences [Beijing]

We measure the pressure dependence of the electrical resistivity and the crystal structure of iron superconductor Sr2VO3FeAs. Below ∼ 10GPa the structure compresses but remains undeformed, with regular FeAs4 tetrahedrons, and a constant Tc. Beyond 10GPa, the tetrahedron strongly distorts, while Tc goes gradually to zero. Band structure calculations of the undistorted structure show multiple-nesting features that hinder the development of an antiferromagnetic (AF) ground state, allowing the appearance of superconductivity. The deformation of the tetrahedra that breaks band degeneracy degrades multiple nesting, thus favouring one particular AF state at the expense of Tc.

Domaines: Supraconductivité [cond-mat.supr-con]

Gaston Garbarino, Ruben Weht, Amadou Sow, Claudine Lacroix, André Sulpice, et al.. Direct observation of the influence of the FeAs4 tetrahedron on superconductivity and antiferromagnetic correlations in Sr2VO3FeAs. EPL - Europhysics Letters, 2011, 96 (5), pp.57002. ⟨10.1209/0295-5075/96/57002⟩. ⟨hal-00966319⟩