Interplay between nematicity and superconductivity in strained pnictides superconductors

G. PASQUINI; J. SCHMIDT; V. BEKERIS; G. LOZANO; M. MARZIALI BERMÚDEZ; HICKS, C.W.; CANFIELD, P.C.; E. FRADKIN

Workshop; 18th International Online Vortex -2021 Conference; 2021

The electronic phase diagrams of a variety of non-conventional superconductors have been described in the context of coupling of multiple orders [1]. A cutting edge topic has emerged from the observation of a true nematic phase [2] where the electronic and structural anisotropies are coupled, and the response is strongly influenced by the formation of nematic domains delimited by twin boundaries. In this context, the relationship between nematic and superconducting orders has attracted abundant interest in the last years. In particular, superconductivity in Ba(Fe1−xCox)2As2 has been shown to compete with nematicity, evidenced by the suppression of orthorhombic distortion as the system undergoes the superconducting transition, and by the observed repulsion between vortices and twin boundaries. On the other hand, a quantum critical nematic point is found near the optimal doping [2]. In this work [3] we show evidence of nematic effects in the mixed superconducting phase of slightly underdoped Ba(Fe1-xCox)2As2. Elasto-resistivity measurements [4] were done under a rotating magnetic field and the analysis of the angular dependence in the mixed superconducting state allows identify single domain detwinned samples. Our results show that although nematicity contributes in a decisive way in the conduction properties in the mixed state, its contributions to the anisotropy properties of the stiffness of the superconducting order parameter is not as significant in these samples. The dependence of T_c with strain and resistive anisotropy is also discussed. References:[1] E. Fradkin, S. A. Kivelson, and J. M. Tranquada, Rev. Mod.Phys. 87, 457 (2015)[2] H.-H. Kuo, J.-H. Chu, J. C. Palmstrom, S. A. Kivelson, andI. R. Fisher, Science 352, 958 (2016)[3] J. Schmidt, V. Bekeris, G. S. Lozano, M. V. Bortulé, M. Marziali Bermúdez, C. W. Hicks, P. C. Canfield,E. Fradkin, and G. Pasquini, Phys. Rev. B 99 064515 (2019). [4] C. W. Hicks, M. E. Barber, S. D. Edkins, D. O. Brodsky, andA. P. Mackenzie, Rev. Sci. Instrum. 85, 065003 (2014).