高压下L10-FePd晶态合金的晶格动力学和弹性

Lattice Dynamics and Elasticity of the L10-FePd Crystalline Alloy under High Pressure

利用密度泛函理论结合晶格动力学理论研究二元晶态合金L10-FePd在压力诱导下的声子谱和声子态密度、弹性模量、泊松比.在0GPa下,考虑电子自旋极化的L10-FePd晶态合金的声子谱在整个布里渊区没有出现虚频,这说明具有铁磁性的L10-FePd晶态合金处于动力学稳定状态.具有L10-FePd晶态合金没有声子谱带隙,说明L10-FePd晶态合金延展性较好.在布里渊区的G点处纵向光学支声子(LO)与横向光学支声子(TO)出现了简并现象,说明体系中存在库仑长程静电交换相互作用.分析体系的弹性模量的变化与泊松比和B/G随压力的变化规律,发现具有铁磁性的L10-FePd晶态合金随压力的增大延展性较好.

The phonon spectra,phonon state density,elasticity modulus and Poisson′s ratio of L1 0-FePd crystalline alloy under pressure induction were studied by density functional theory and lattice dynamic theory.The phonon spectrum of the L1 0-FePd crystalline alloy with conceding the electron spin polarization have no imaginary frequency throughout the Brillouin zone at 0 GPa. The results show that the ferromagnetic L1 0-FePd crystalline alloy is in a state of dynamic stability. The L1 0-FePd crystalline alloy has no phonon frequency gap,indicating that the L1 0-FePd crystalline alloy has good ductility. The longitudinal optical phonons (LO) and the transverse optical phonons (TO) at the G-point of the Brillouin zone are degenerate,indicating that long range Coulomb electrostatic exchange interaction in the system. It was found that the L1 0-FePd crystalline alloy with ferromagnetism has better ductility with increasing pressure.