Departamento de Física, FCEyN, UBA – CONICET
«Experimental approaches for exploring the interplay between nematicity and unconventional superconductivity»
The relationship between superconductivity, nematicity, and magnetism has been a key topic in
the study of iron-based superconductors, and several mechanisms for unconventional
superconductivity that invoke an interplay among these phenomena remain under debate. In this
talk, I will review a set of experimental techniques that allow us to explore specific aspects of this
interplay in single crystals of these materials.
The role of magnetic fluctuations in superconductivity can be investigated through nuclear
magnetic resonance experiments [1], although these provide only indirect information about the
role of nematicity. An alternative approach is to study the coupling between nematic and
superconducting order parameters. A key challenge is that the spontaneous formation of nematic
domains can average macroscopic manifestations of nematicity to zero. Consequently, the
relationship between nematicity and superconductivity can be investigated either through
macroscopic measurements under uniaxial stresses that align nematic domains, or through
local/microscopic probes. I will show how to extract information about the nematic-
superconducting coupling from the anisotropies in the superconducting stiffness revealed by
electrical transport measurements under uniaxial stresses and rotating magnetic fields [2], as well
as from anisotropic vortex-pinning properties that can be probed through current–voltage
measurements under uniaxial stress using a technique that we have recently adapted [3]. Finally, I
will highlight the importance of local probes such as scanning tunneling microscopy, which can
provide complementary information without the need for externally applied uniaxial stress.
- Q.-P. Ding, et al.; Phys. Rev. Lett. 134 (2025) 226002.
- J. Schmidt, et al.; Phys. Rev. B 99, (2019) 064515.
- F. Castillo Menegotto, et al; J Low Temp Phys 222, (2026) 72.