Effects of Pressure on Structural, Mechanical, and Electronic Properties and Stability of Fe_xSi_y Compounds

Abstract

Herein, the pressure dependence of the structural, mechanical, and electronic properties is investigated for Fe2Si, FeSi, Fe3Si, α‐FeSi2, β‐FeSi2, Fe5Si3, and Fe11Si5 in the pressure range of 0–100 GPa based on density functional theory. The calculated lattice constants are in good agreement with the experimental results. The order of the thermodynamic stability of the seven structures is FeSi > Fe5Si3 > Fe2Si > β‐FeSi2 > Fe11Si5 > α‐FeSi2 > Fe3Si. The electronic properties are analyzed including density of states and band structures. The mechanical properties of FeSi, Fe2Si, Fe5Si3, α‐FeSi2, and β‐FeSi2 are studied thoroughly: The elastic constants are obtained under different pressures; the mechanical stability under the considered pressures is evaluated by the stability criteria. The results show that FeSi, Fe5Si3, and β‐FeSi2 are mechanically stable at pressures from 0 to 100 GPa; Fe2Si is unstable under compression; and α‐FeSi2 is unstable in the range of 60–100 GPa. The values of B, G, and E are calculated, which indicate that the ability to resist deformation of the material increases with the increase in pressure. The B/G values are calculated, suggesting that both Fe5Si3 and Fe2Si are ductile materials; the brittle–tough transition is observed in FeSi, α‐FeSi2, and β‐FeSi2.

Pressure‐Induced Synthesis of Homogeneously Dispersed Sn/SnO2/C Nanocomposites as Advanced Anodes for Lithium‐Ion Batteries

“…[5,6,17] Furthermore, the intensity (Figure 2b), which arise from D and G peaks of carbon materials, respectively. [7] In addition, sample-I shows two peaks around 107.2 and 204.3 cm À1 , which are attributed to the E g and A 1g vibration modes of SnO, respectively ( Figure 2b), [27] again indicating SnO is formed. Sample-II shows a peak around 621.4 cm À1 , which is attributed to A 1g vibration mode of SnO 2 , again indicating SnO 2 is formed.…”