Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 38: Superconductivity: Theory

TT 38.5: Vortrag

Freitag, 9. September 2022, 10:30–10:45, H23

Charge 4e skyrmion superconductivity? — •Gabriel Rein^1,2, Marcin Raczkowski¹, and Fakher F. Assaad^1,2 — ¹Institut für Theoretische Physik und Astrophysik Universität Würzburg, 97074 Würzburg, Germany — ²Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany

We consider a dynamically generated quantum spin Hall (QSH) state which has as characteristic that skyrmion excitations of the SO(3) order parameter carry charge 2e. In Refs. [1,2] a model was defined with a single parameter λ that drives a continuous transition akin to deconfined quantum criticality from a QSH insulator to an s-wave superconductor via the condensation of charge 2e skyrmions. Our aim here is to modify this Hamiltonian by adding flavor degrees of freedom N_f, such that the charge of the skyrmion reads N_f 2 e. In this talk we will map out the phase diagram of the model at N_f = 2. Although, to date charge 4e skyrmion superconductivity remains elusive, the phase diagram in the N_f versus λ plane is very rich with additional Kekule ordered phases.

[1] Y. Liu, Z. Wang, T. Sato, M. Hohenadler, C. Wang, W. Guo, and F. F. Assaad, Nat. Commun. 10 (2019) 2658

[2] Z. Wang, Y. Liu, T. Sato, M. Hohenadler, C. Wang, W. Guo, F. F. Assaad, Phys. Rev. Lett. 126 (2021) 205701