Electronic Structure and Physical Properties of ABC2 (A = Zn, B = Si, Ge, Sn, and C = P, As) Ternary Pnictide Semiconductors

Abstract

Band structure calculations of ABC 2 (A ¼ Zn, B ¼ Si, Ge, Sn, and C ¼ P, As) ternary pnictides performed using the semi-relativistic 'tight binding linear muffin tin orbital' (TB-LMTO) method within local density approximation under ambient and high pressures are reported here. The energy gap at ambient pressure is found to be direct in all the cases and the nature of the gap crucially depends on the manner in which the d electrons of atom A are treated. The equilibrium lattice constants, the bulk modulus, its first derivative and the metallisation volume obtained from the total energy calculations are also reported. More generalized equations connecting cell volume (V 0 ) and microhardness (H) as well as V 0 and melting point (q m ) for pnictides are established, by use of which the values of H and q m for some pnictides are predicted for the first time in cases where experimental values are not known.

Effect of cation substitution on electronic band structure of ZnGeAs2 pnictides: A mBJLDA approach

“…Even the accuracy of our calculated band gaps w.r.t. experiment is very high as compared to other theoretical results [15,27] for all compounds. The band gaps for studied compounds are found in range 0.51-1.27 eV.…”

Pressure Induced Structural Phase Transition, Metallization and Superconductivity in SodiumIodide (NaI)

“…The final energy convergence is within 10 -5 Ry. The calculated total energies were fitted to Murnaghan's equation of state (EOS) [17], to determine the bulk modulus and pressure derivative of bulk modulus B 0 1 . We have obtained, (i) Normal pressure band structure and density of states NaI (with NaCl structure) (ii) High pressure band structure and density of states of NaI (with CsCl structure)…”

“…4) indicating metallization in NaI. When pressure increases (reduced volume decreases)the value of the DOS at fermi energy, E F (N(E F )) increases [17]. The normal pressure DOS trend is changed under high pressure.…”

Electronic structure, chemical bonding and optical properties of the nonlinear optical crystal ZnGeP2by first-principles calculations

“…Only valence electrons are taken into account, corresponding to Zn: 3d 10 4s 2 , Ge: 4s 2 4p 2 and P: 3s 2 3p 3 electronic configurations in USP. The d-electrons of Zn are treated as valence electrons unlike the earlier pseudo-potential based calculations [34]. The plane-wave cutoff energy is fixed at 600.00 eV in our calculations.…”