ORAL: Interplay between nematic domains and superconducting properties in Ba(Fe1−xCox)2As2.

G. PASQUINI; V. BEKERIS; G. LOZANO; J. SCHMIDT; V. BORTULE; M. MARZIALI BERMÚDEZ; R. BORZI; S. A. GRIGERA; E. FRADKIN

Bariloche

Simposio; Latinoamerican Symposium of Solid State Physics (SLAFES)XXIII; 2018

The electronic phase diagrams of highly correlated systems, particularly of a variety of non-conventionalsuperconductors, have been described in the context of an intertwining of multiple orders [1]. A cutting edgetopic has emerged recently from the observation of strongly anisotropic electronic states in both cuprates andin Fe based superconductors. A Curie-law divergence in the nematic susceptibility indicates a transition to anematic phase [2], where the transport anisotropy is coupled to magnetic and structural anisotropies, and theresponse is dominated by the formation of nematic domains. Among the Fe based pnictides superconductors, theBa(Fe1−xCox)2As2 family has been the most extensively studied. In this family, the optimal doped compoundsare those that present the largest nematic phase, lying very near Tc in the phase diagram [2].However, up to now,the coupling between nematicity and superconductivity has been poorly addressed.The nematic susceptibility is generally measured by means of elasto-resistivity experiments, a powerful technique involving a number of non-trivial technical challenges. Recently, a novel piezoelectric-based apparatus toachieve large sample strains at cryogenic temperatures, with compensation of undesirable piezoelectric thermaldeformations, has been designed [3]. In a recent collaboration, that includes several experimental and theoretical groups, such device has been installed to perform elasto-resistiviy measurements at low temperatures andorientable magnetic fields, in the Low Temperature Laboratory of FCEyN, UBA.In the present work we report recent results, obtained by means of dc and ac elasto-resistiviy measurements,which explore the interplay between the amplitude and frequency of sample strain with the formation of nematicdomains, and its consequence in the superconducting transport response. A model that describes the interactionbetween nematic domain walls and superconducting vortex is also presented.[1] E. Fradkin et al., Rev. Mod. Phys. 87, 457 (2015).[2] H-H Khuo et al., Science 352, 960 (2016).[3] C. W. Hicks et al., Rev. Sci. Instr. 85, 065003 (2014)