Shi Wen-Hao, Deng Zun-Yi, Feng Hong-Jian
School of Physics, Northwest University, Xi'an 710127, People's Republic of China.
J Phys Condens Matter. 2024 Feb 28;36(21). doi: 10.1088/1361-648X/ad2762.
The studies for the interaction of energetic particles with matter have greatly contributed to the exploration of material properties under irradiation conditions, such as nuclear safety, medical physics and aerospace applications. In this work, we theoretically simulate the non-adiabatic process for GaAs upon proton irradiation using time-dependent density functional theory, and find that the radial propagation of force on atoms and the excitation of electron in GaAs are non-synchronous process. We calculated the electronic stopping power on proton with the velocity of 0.1-0.6 a.u., agreement with the previous empirical results. After further analyzing the force on atoms and the population of excited electrons, we find that under proton irradiation, the electrons around the host atoms at different distances from the proton trajectories are excited almost simultaneously, especially those regions with relatively high charge density. However, the distant atoms have a significant hysteresis in force, which occurs after the surrounding electrons are excited. In addition, hysteresis in force and electron excitation behavior at different positions are closely related to the velocity of proton. This non-synchronous propagation reveals the microscopic dynamic mechanism of energy deposition into the target material under ion irradiation.
高能粒子与物质相互作用的研究极大地推动了对辐照条件下材料特性的探索，如核安全、医学物理和航空航天应用等领域。在这项工作中，我们利用含时密度泛函理论对质子辐照砷化镓的非绝热过程进行了理论模拟，发现砷化镓中原子上力的径向传播与电子激发是非同步过程。我们计算了速度为0.1 - 0.6原子单位的质子的电子阻止本领，与先前的经验结果相符。在进一步分析原子上的力和激发电子的布居数后，我们发现质子辐照下，距质子轨迹不同距离处的主体原子周围的电子几乎同时被激发，尤其是那些电荷密度相对较高的区域。然而，远处的原子在力的作用上有显著的滞后现象，这发生在周围电子被激发之后。此外，不同位置处力的滞后和电子激发行为与质子速度密切相关。这种非同步传播揭示了离子辐照下能量沉积到靶材料中的微观动力学机制。
