基于第一性原理对U_3O_8的磁性和动力学性质的研究

基于第一性原理的密度泛函理论,分别用(GGA)和GGA+U方法对U3O8的磁性和动力学性质做了一定的研究,此外,在研究磁性的过程中,GGA+U+SO方法也被考虑其中.优化得到的不同磁性态下的晶格参数和能量均与实验值吻合的非常好.用铁磁和反铁磁下的能量差,E=EAFM-EFM,作为磁性判断的一个标准,计算发现U3O8的顺磁态为其基态.对于动力学性质的研究,不同于以往研究所采用的D3d3点群,本文采用C2v晶体点群,对U3O8的光谱属性重新进行归属和更正,得到了与实验值基本一致的结果.

First-principles studies of magnetic and dynamical properties of U3O8

The magnetic, dynamical properties of U308 were performed using density-functional theory （DFT） based on first-principles theory in generalized gradient approximation （GGA） and GGA＋U formalism. The optimized U3Os lattice parameters and calculated energy for FM, AFM and paramagnetic U308 agree reasonably well with the recent experimental data. Especially, GGA＋ U＋SO is taken into account to the FM and AFM phases in the article. The energy difference between FM and AFM ordering, △ E = EAFU- EFM, as an indicator of the magnetic stability, paramagnetic U308 is the magnetic. In addition, the vibration modes were re-assigned using the crystal point group C2. instead of the point group of D3d3 in previous study. The predicted results agree well with available experimental data and other theoretical calculations.