利用第一原理模擬計算La(Mg1/2,Ti1/2)O3材料，以密度泛函微擾理論及線性響應的方式，來研究微波介電材料La(Mg1/2,Ti1/2)O3在Γ點上的聲子行為，並以羅倫茲模型對於材料介電特性跟材料的晶格振盪的關係，來探討利用拉曼光譜實驗及紅外光光譜實驗於La(Mg1/2,Ti1/2)O3材料的結果輔以第一原理模擬計算所得到的資訊，來研究La(Mg1/2,Ti1/2)O3材料的聲子行為與介電特性的關係。 We use first-principles to begin the simulation on the microwave dielectric material La(Mg1/2,Ti1/2)O3. In our calculations, we use the Density-Functional Perturbation Theory and linear response method to get the phonons at Γ point. And then, we make a few experimental observations like Raman spectrum and FTIR spectrum on the microwave dielectric material La(Mg1/2,Ti1/2)O3. According to our calculations, the calculated eigenvalues and corresponding eigenvectors of each vibration mode at Γ point provide a great help on assignment of our experimental observations. Finally, we use the Lorentz model to study the relation between vibration modes and dielectric properties on the microwave dielectric material La(Mg1/2,Ti1/2)O3.
