Linear-Scaling and Memory-Efficient Implementation of van-der-Waals Interaction (DFT-D3) for Large Systems

The van der Waals (vdW) interaction is ubiquitous in materials and is long-range by nature. To facilitate vdW-included atomic simulations in large systems with tens of thousands of atoms, we developed LASP-D3, a Compute Unified Device Architecture (CUDA) implementation of the DFT-D3 method on graphics processing unit (GPU) devices, which realizes fast vdW corrections compatible with state-of-the-art machine-learning potential calculations. Our implementation achieves a linear-scaling time complexity, O(N), for large periodic systems, being up to 2 orders of magnitude faster than all current versions for systems above 100,000 atoms, and significantly reduces GPU memory consumption compared to existing PyTorch-based GPU implementations. By combining LASP-D3 with the generalized global neural network potential developed by us, we show that the leading solid electrolyte LiTaCl₆ can achieve high conductivity, where the vdW interaction plays a key role in governing Li-ion diffusion and the simulated conductivity reproduces experimental measurements.