标题: | 电子非弹性表面散射截面之记忆效应探讨 Study of the memory effect in inelastic scattering cross sections of electrons near a surface |
作者: | 许育豪 Yu-Hao Hsu 桂正楣 Cheng-May Kwei 电子研究所 |
关键字: | 表面激发;连续非弹性散射;记忆效应 |
公开日期: | 2002 |
摘要: | 过去的理论模式,总是将每一次电子与固体的非弹性碰撞过程,视为独立的事件。这意味着每次散射截面,对于前次散射行为不具有任何记忆效力 ;然而我们推测,散射事件应该会藉由电子能量在固体内之转移,影响下一次电子散射的行为。这个研究的主要目标,就是要建立一个可靠的模式来呈现“连续非弹性交互作用间的记忆效应”。 根据介电理论和柏桑定律,我们针对一个以平行轨迹运动于固体外的测试电子之边界问题,利用柏桑方程式之解,建立了考虑记忆效应的微分非弹性反平均自由行程与非弹性反平均自由行程公式。 我们计算了发生一次非弹性散射,而损失部分能量且平行于铜及矽表面运动之电子,其发生连续非弹性交互作用之微分非弹性反平均自由行程与非弹性反平均自由行程。我们关注能量范围在300 - 1000电子伏特的电子,与固体非弹性交互作用的记忆效应,并探讨记忆效应所造成的影响。 It was generally assumed that two successive inelastic interactions between an electron and the solid are independent of each other. This means that the electron keeps no memory on its previous interactions. However, any previous interaction should have some influence on the succeeding interaction due to the energy loss of the electron in its previous interaction. The aim in this work was to establish a reliable model to describe the memory effect between successive inelastic interactions. Based on the dielectric response theory and the Poisson law, we set up formulae for the differential and the total inelastic inverse mean free paths with memory effect, by solving the Poisson equation and matching the boundary conditions for a probe electron with a parallel trajectory outside the solid. The differential and the total inelastic inverse mean free paths for the successive interactions were calculated for electrons moving parallel to the surface of Cu and Si by considering the memory effect. The memory effect in the energy loss of inelastic interactions for electrons with energies 300 – 1000 eV was investigated. The effect was observable. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#NT910428095 http://hdl.handle.net/11536/70422 |
显示于类别: | Thesis |