论文标题
金属玻璃剪切带中的等离子能量损失
Plasmon energy losses in shear bands of metallic glass
论文作者
论文摘要
观察到，观察到，观察到由冷滚动Al $ _ {88} $ y $ _ {7} $ fe $ _ {5} $金属玻璃产生的剪切带，以显示沿其传播方向的交替密度变化。电子能量损耗光谱（EEL）用于研究剪切带和周围的体积等离激子的能量损耗。使用开源Python模块（Hyperspy）精确确定了反映阻尼的峰宽度（FWHM）的峰值宽度（FWHM）的变化（FWHM）的能量变化，以适应具有Lorentzian功能的等离子体和零损失峰的形状。计算出相对于矩阵的明亮和深色剪切带段的最大散装等离子能移位分别为38和14 meV。观察到阻尼对于较密的区域的阻尼更大。此处提供的分析表明，等离子的变化是由两个贡献引起的：（i）由于中距离（MRO）的变化，剪切带段中的可变阻尼。这会影响静态结构因子s（k），这反过来又导致Ziman-Baym公式减少或增加阻尼。 （ii）在零momentum等离子体频率公式$ e_p（q = 0）$中出现的离子密度和有效电子质量是耦合的，并引起等离子体能量的较小变化。该模型预测等离子能量在MEV的顺序中变化。
Shear bands resulting from plastic deformation in cold-rolled Al$_{88}$Y$_{7}$Fe$_{5}$ metallic glass were observed to display alternating density changes along their propagation direction. Electron-energy loss spectroscopy (EELS) was used to investigate the volume plasmon energy losses in and around shear bands. Energy shifts of the peak centre and changes in the peak width (FWHM) reflecting the damping were precisely determined within an accuracy of a few meV using an open source python module (Hyperspy) to fit the shapes of the plasmon and zero-loss peaks with Lorentzian functions. The maximum bulk plasmon energy shifts were calculated for the bright and dark shear band segments relative to the matrix to be about 38 and 14 meV, respectively. The damping was observed to be larger for the denser regions. The analysis presented here suggests that the changes in the plasmons are caused by two contributions: (i) Variable damping in the shear band segments due to changes in the medium-range order (MRO). This affects the static structure factor S(k), which, in turn, leads to either reduced or increased damping according to the Ziman-Baym formula. (ii) The ionic density and the effective electron mass appearing in the zero-momentum plasmon frequency formula $E_p(q=0)$ are coupled and give rise to small variations in the plasmon energy. The model predicts plasmon energy shifts in the order of meV.
