Abstract:

The elastic, optical properties and Debye temperature of LnN were investigated by means of firstprinciples calculations based on density functional theory. The calculated elastic constants show that the B/G ratio of light LnN (Ln=La,Ce,Pr,Nd,Pm,Sm,Eu） is larger than 175 except LaN, indicating that th
ese crystals are ductile, while the ratio of heavy LnN (Ln=Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu) is smaller than 1.[KG-*3]75 except GdN, indicating that these crystals are brittle. The optical property shows that the static dielectric constant and reflection coefficient of HoN are the highest among those of all the LnN compounds, and shows that refractive index of LaN is the highest among those of all the LnN compounds. The Debye temperature of LnN is between 300—500 K, indicating that the order of magnitude of the phonon vibration is 10¹³ s^-1.

Key words:  firstprinciples calculations, elastic property, optical property, Debye temperature