Electronic structure and energies of interatomic bonds in the TiSi2 compound with a C49 crystal structure
Tóm tắt
Full-electron calculations of the electronic structure of the TiSi2 compound in the structural modification C49 are performed using the augmented-plane-wave method. The total energy, the electronic band structure, and the density of states are calculated for an extended translational unit cell Ti4Si8, which is formed during the growth of a silicon nanowire on a p-Si substrate. Calculations are also carried out for two orthorhombic unit cells of the nonstoichiometric compositions Ti3Si9 and Ti5Si7. The energies of the interatomic bonds are determined to be E
Si-Si = 1.8 eV, E
Ti-Ti = 2.29 eV, and E
Ti-Si = 4.47 eV. The dependence of the total energy of the unit cell E
tot(V) on the unit cell volume V is obtained by optimizing the unit cell volume. The bulk modulus B
0 = 132 GPa is determined from the Murnaghan equation of state for solids and the dependence E
tot (V). This value of the bulk modulus is used to estimate the activation energy for interstitial diffusion of silicon atoms Q
i(Si) ≈ 0.8 eV.
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