Title: Exploring the Interplay Between Nematicity and Superconductivity Through Vortex System Properties
When: Thursday, December 12, 2024, 11:00
Place: Department of Condensed Matter Physics, Faculty of Sciences, Module 3, Seminar Room (5th Floor)
Speaker: Gabriela Pasquini, Departamento de Física, FCEN, Universidad de Buenos Aires, Buenos Aires, Argentina IFIBA, CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina.
Superconducting materials are widely used today in different applications and postulated as key for novel developments, as qubits in quantum computing. However, whereas conventional superconductivity is explained from first principles in the framework of BCS theory, the mechanism responsible for unconventional superconductivity is still under discussion. In this context , it has been suggested that the coupling between nematic and superconducting order could play a central role in the superconducting properties of several unconventional superconductors. In fact, a nematic phase develops in the normal state of several families of iron-based superconductors, evidenced in a simultaneous symmetry breaking of both electronic and structural properties, driven by the electronic degrees of freedom. The macroscopic behavoir observed in this broken-symmetry phase is strongly influenced by the formation of nematic domains. However, the interplay between nematic and superconducting order still has several open questions, including the role of these domain and their boundaries. Our group has studied this topic during the last years, both through experiments and numerical simulations [1-4]. The experimental approach primarily focuses on low temperature transport experiments in single crystals under uniaxial stress. We have recently developed a technique that allows for the measurement of transport properties under controlled deformation and stress at low temperatures in the presence of a rotating magnetic field. Our theoretical approach relies on a phenomenological Ginzburg-Landau model in which superconducting and nematic order parameters may be coupled. Numerical results are obtained by solving the time-dependent Ginzburg-Landau equations using pseudospectral methods. In this talk I introduce the topic, and discuss some aspect regarding the influence of the nematic order and nematic domains in the superconducting mixed phase. Our aim is to identify key features able to be predicted by phenomenological models and observed experimentally. I present numerical results regarding some consequences expected in the vortex lattice structure, effective superconducting anisotropy, and flux flow properties and discuss these in terms of existing and potential future experimental evidence.
References
- Nematicity in the superconducting mixed state of strain detwinned underdoped Ba(Fe1-xCox)2As2, 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).
- Vortices in a Ginzburg Landau Theory of superconductors with nematic order, R. S. Severino, P. D. Mininni, E. Fradkin, V. Bekeris, G. Pasquini, and G. S. Lozano, Phys. Rev. B 106, 094512 (2022).
- Ginzburg-Landau approach to the vortex–domain wall interaction in superconductors with nematic order, R. S. Severino, P. D. Mininni, E. Fradkin, V. Bekeris, G. Pasquini, and G. S. Lozano, Phys. Rev. B 109, 094513 (2024).
- Vortex motion in nematic superconductors, F. Castillo Menegotto et al., in preparation.
