Alex Petrovic Seminar : vTools Events

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Alex Petrovic Seminar

#crystals #dynamics #electromagnetic-fields #Magnetism

Title: Helicity Inference and Control in Magnetic Architectures for Quantum Computation

Abstract: In non-collinear spin textures such as magnetic skyrmions, the helicity −𝜋 < 𝜑0 ≤ 𝜋 describes the orientation of the local spin rotation axis relative to the helical wavevector. The value of 𝜑0 influences the dynamics of skyrmions, as well as their interplay with external electromagnetic fields and ordered states. In particular, the Rashba-Edelstein interaction between a skyrmion and a vortex in a proximate superconductor is suppressed for 𝜑0 = ±𝜋/2 [1], thus raising the possibility of creating a hybrid topological soliton whose stability is governed by 𝜑0.

Motivated by the prospect of building a two-dimensional topological superconducting platform with controllable vortices [2,3], I will present evidence for helicity switching at superconductor/chiral magnet interfaces, driven by competition between dipolar and Dzyaloshinskii-Moriya (DMI) interactions. Magnetic force microscopy can also reveal the impact of helicity on skyrmion-vortex coupling, illustrated by our observed amplification of Néel 𝜋 skyrmion radii when covered by a superconductor. Finally, I will consider centrosymmetric skyrmion crystals, where – in contrast with interfacial systems – the lack of any global DMI creates a near-degenerate helicity landscape, tunable by electric fields and currents. I will discuss possible techniques for local helicity control in these materials, with applications in both topological and analog quantum computing [4].

[1] K. M. D. Hals, M. Schecter, and M. S. Rudner, Phys. Rev. Lett. 117, 017001 (2016).

[2] S. Rex, I. V. Gornyi, and A. D. Mirlin, Phys. Rev. B 100, 064504 (2019).

[3] A. P. Petrović et al., Phys. Rev. Lett. 126, 117205 (2021).

[4] A. P. Petrović, et al., Rev. Mod. Phys. 97, 031001 (2025).