Skyrmion Quantum Diode Prototype: Bridging Micromagnetic Simulations and Quantum Models

Abstract

Magnetic skyrmions are topologically protected spin textures known for their robustness against perturbations. Their topological stability makes them robust information carriers, ideal for tackling a key challenge in quantum computing: creating reliable, one-way links between different types of qubits. In this proof-of-concept study, we introduce a novel device - the skyrmion quantum diode - based on skyrmion qubits. Our approach combines classical micromagnetic simulations, achieving skyrmion diameters as small as 3 nm, with quantum circuit models inspired by superconducting qubits. In this work, we demonstrate: (i) unidirectional skyrmion transport via the skyrmion Hall effect in asymmetric junctions, spanning length scales from 20 nm down to 3 nm; (ii) potential compatibility with flux-tunable quantum architectures; and (iii) preliminary insights into anharmonicity in skyrmion-based qubit systems. These results establish both the operational feasibility and the scaling behavior necessary for a hybrid skyrmion-quantum platform. Our work outlines a path toward integrating skyrmion based quantum components into practical device architectures, enabling low-dissipation, unidirectional quantum information transport. This capability is crucial for scalable quantum computing, spintronic logic, and hybrid quantum systems, and opens opportunities for chipscale, pump-free isolators and directional quantum links that enhance readout fidelity, reduce cryogenic load, and support modular skyrmion-superconducting processors

Figures (4)

• Figure 1: Micromagnetic simulation snapshots showing forward (left $\rightarrow$ right) and reverse (right $\rightarrow$ left) propagation of Néel skyrmions through an asymmetric T-junction diode for three target core diameters: $\sim$20 nm, $\sim$10 nm, and $\sim$3 nm. In forward bias, the skyrmion Hall effect steers skyrmions into the widening side of the junction, enabling transmission. In reverse bias, Hall deflection toward the narrowed side; in all types of skyrmions, this leads to reflection back into the injection arm. Time Stamps indicate intervals between frames for each size case.
• Figure 2: Fidelity mapping. (a) Schematic geometric potential. (b) Fidelity values for a single skyrmion qubit under varying diode efficiency $\eta$. Middle: forward fidelity $F_{L\to R}$ (initial $\lvert 0\rangle$, measured in $\lvert 1\rangle$). Right: reverse fidelity $F_{R\to L}$ (initial $\lvert 1\rangle$, measured in $\lvert 0\rangle$). Horizontal axis: evolution time $t$ (in units of $1/J$). Vertical axis: diode efficiency $\eta$.
• Figure 3: Comparison of the helicity–skyrmion qubit potential and quantized levels with and without a diode-efficiency term. (a) Conventional double-well potential with the lowest eigen-energies drawn as constrained horizontal segments (only where $V(\phi_0)\le E_n$). (b) Diode-modified potential $V(\phi_0)=K_2^{\mathrm{eff}}\cos(2\phi_0)-\bar{E}_z\cos\phi_0$ with $K_2^{\mathrm{eff}}=\eta K_2$, where the efficiency factor $\eta$ renormalizes the $\cos(2\phi_0)$ term and yields greater level-spacing nonuniformity---i.e., stronger anharmonicity---relative to (a).
• Figure 4: Skyrmion-transmon tuning. (a) Schematic circuit. (b) Transmon qubit resonance frequency plot as a function of $\epsilon$, the imbalance between Josephson energies, and $\phi_e$, the reduced modulation flux.