The diffusion of defects in crystalline materials¹ controls macroscopic behaviour of a wide range of processes, including alloying, precipitation, phase transformation and creep². In real materials, intrinsic defects are unavoidably bound to static trapping centres such as impurity atoms, meaning that their diffusion is dominated by de-trapping processes. It is generally believed that de-trapping occurs only by thermal activation. Here, we report the direct observation of the quantum de-trapping of defects below around one-third of the Debye temperature. We successfully monitored the de-trapping and migration of self-interstitial atom clusters, strongly trapped by impurity atoms in tungsten, by triggering de-trapping out of equilibrium at cryogenic temperatures, using high-energy electron irradiation and in situ transmission electron microscopy. The quantum-assisted de-trapping leads to low-temperature diffusion rates orders of magnitude higher than a naive classical estimate suggests. Our analysis shows that this phenomenon is generic to any crystalline material.

晶体材料中缺陷的扩散¹控制着各种过程的宏观行为，包括合金化、沉淀、相变和蠕变². 在实际材料中，固有缺陷不可避免地与杂质原子等静态俘获中心结合，这意味着它们的扩散主要由去俘获过程控制。一般认为，去捕获仅通过热激活发生。在这里，我们报告了对低于德拜温度约三分之一的缺陷的量子去捕获的直接观察。我们通过使用高能电子辐照和原位透射电子显微镜在低温下触发脱离平衡，成功地监测了自填隙原子簇的去捕获和迁移，这些原子簇被钨中的杂质原子强烈捕获。量子辅助的去捕获导致低温扩散速率比简单的经典估计所暗示的高几个数量级。