DQMP - Informal Seminar - 29.11.2022 - 02:00 pm - Mario Cuoco

29.11.2022 14:00 – 15:30

Superconducting orbitronics effects
Mario Cuoco

Orbital degrees of freedom play a key role in setting out striking effects when dealing with low dimensional noncentrosymmetric superconductors. A relevant concept in this context is represented by the orbital Rashba coupling. I show that, by varying the strength of the orbital Rashba interaction, the superconducting phase can undergo a 0−π transition with the π-phase being marked by a non-trivial sign change of the superconducting order parameter between different orbitals [1]. Then, I discuss the physical mechanisms for achieving an unconventional orbital pair-density wave [2]. Breaking of time-reversal and point-group spatial symmetries can have a profound impact on superconductivity. Here, I show that in two-dimensional spin-singlet superconductors with unusually low degree of spatial symmetry content, vortices with supercurrents carrying orbital angular momentum around the core can form and be energetically stable [2]. The vortex has zero net magnetic flux since it is made up of counter-propagating Cooper pairs with opposite orbital moments. The orbital vortex has a characteristic pattern with a pronounced angular anisotropy that deviates from the profile of conventional magnetic vortices. Finally, I will discuss the Edelstein effects arising in multi-orbital superconductors that lack inversion symmetry. It is known that the flow of supercurrent can induce a nonvanishing magnetization, a phenomenon which is at the heart of nondissipative magnetoelectric effects. For electrons carrying spin and orbital moments, a question of fundamental relevance deals with the orbital nature of magnetoelectric effects in conventional spin-singlet superconductors with Rashba coupling. Remarkably, we find that the supercurrent-induced orbital magnetization is more than 1 order of magnitude greater than that due to the spin, giving rise to a colossal magnetoelectric effect [3]. An overview on materials which can exhibit these phenomena as well as orbitally driven transport and topological properties are also presented [4,5,6].


[1] M. T. Mercaldo et al., Phys. Rev. Applied 14, 034041 (2020).
[2] M. T. Mercaldo et al., Phys. Rev. B 105, L140507 (2022).
[3] L. Chirolli et al., Phys. Rev. Lett. 128, 217703 (2022).
[4] Y. Fukaya et al., npj Quantum Materials 7, 99 (2022).
[5] D. Go et al., EPL 135, 37001 (2021).
[6] Y. Fukaya et al., arXiv:2209.11077 (2022).

Organisé par: Prof. Andrea Caviglia


Bâtiment: Ecole de Physique

Salle MaNEP

Organisé par

Département de physique de la matière quantique


Mario Cuoco, CNR-SPIN

entrée libre


Catégorie: Séminaire