Uncovering multi-channel magnetic hopfion annihilation via a single-node, billion-spin-scale atomistic framework
2026-05-25 • Software Engineering
Software Engineering
AI summaryⓘ
The authors present SpinX, a new software tool designed to simulate magnetic materials at the atomic level using powerful GPUs. It speeds up previously slow calculations by using clever math tricks to handle complex magnetic interactions efficiently, even in large 3D lattices. SpinX supports various simulation methods and was tested to match known physics results, also revealing two different ways a certain magnetic structure can disappear. Overall, the authors show that SpinX can handle huge simulations much faster than before.
Spin HamiltonianLandau-Lifshitz-Gilbert dynamicsMonte Carlo samplingMagnetic hopfionTensor convolutionFFT (Fast Fourier Transform)Atomistic spin simulationsGPU accelerationNudged elastic band methodCrystallographic sublattice
Authors
Qichen Xu, Anna Delin
Abstract
Modern atomistic spin simulations combine long stochastic trajectories, thermodynamic sampling, static optimization and multi-image transition-path workflows, all of which rely on repeated evaluation of spin Hamiltonians and become computationally prohibitive on the large lattices required for three-dimensional magnetic textures. We introduce SpinX, a GPU-native atomistic spin simulation framework built around a unified Hamiltonian interface and multiple user-selectable computational backends. Its core is a crystallographic sublattice decomposition that reformulates translationally invariant spin interactions as multi-channel tensor convolutions, enabling dense, sparse and FFT-based convolution backends, while irregular systems are handled by pair-list evaluation and long-range dipolar fields by reciprocal-space FFT. Implemented in JAX, SpinX supports deterministic and stochastic Landau-Lifshitz-Gilbert dynamics, Monte Carlo sampling, static optimization, dynamical spectroscopy and string and geodesic nudged elastic band transition-path calculations on heterogeneous accelerator platforms. A validated mixed-precision mode combines fp32 field evaluation with fp64 spin-state propagation. We validate SpinX against analytical single-spin dynamics, finite-size thermodynamics of bcc Fe and transverse dynamic structure factors. Performance benchmarks show peak throughput exceeding 10 billion spin-site operations per second on a single accelerator and aggregate single-node workloads of over 1 billion atomic spins. Applying this framework to an exchange-stabilized magnetic hopfion, we uncover two competing annihilation channels on a million-spin atomistic lattice: a previously reported axial-collapse pathway and a distinct lateral-rupture pathway with a different transition morphology and activation barrier.(Due to arXiv's limit, the abstract shown here is a shortened version)