YIG及Bi－YIG薄膜材料的光吸收谱的微观机理研究

Microscopic Mechanism of Optical Absorption Spectra in the YIG and Bi YIG Thin Films

采用ＤＶ－Ｘα方法计算了ＹＩＧ薄膜的电子结构，在能态密度的基础上，得出了导致光吸收的两种电荷转移跃迁。在１２～２０ｃｍ－１×１０３波长范围，计算出了与实验一致的吸收谱。Ｂｉ３＋离子的掺入，增大了跃迁的振子强度，其增大量与铋离子的浓度成正比。在此基础上得出的Ｂｉ－ＹＩＧ的理论谱与实验谱符合得较好。

Using DV Xα method,we calculated the electronic structure of YIG.We found that there were two types of charge transfer transitions under 3.5 eV,which were the main origin of optical absorption of YIG on the basis of the total density of states and the partial density of states of YIG film.In the wavelength from 12cm -1 ×10 3 to 20cm -1 ×10 3,we calculated the optical absorption spectra which were consistent with the experiment spectra of YIG.The Bi substitution led to the increase of oscillator strength.The increases of oscillator strength were proportional to the density of bismuth in YIG.The calculated optical absorption spectra of Bi YIG were in good agreement with the experiment results.