Investigation of structural, electronic, elastic and optical properties of Cd1-x-yZnxHgyTe alloys

Abstract

Structural, optical and electronic properties and elastic constants of Cd1-x-yZnx HgyTe alloys have been studied by employing the commercial code Castep based on density functional theory. The generalized gradient approximation and local density approximation were utilized as exchange correlation. Using elastic constants for compounds, bulk modulus, band gap, Fermi energy and Kramers–Kronig relations, dielectric constants and the refractive index have been found through calculations. Apart from these, X-ray measurements revealed elastic constants and Vegard’s law. It is seen that results obtained from theory and experiments are all in agreement.

Low temperature synthesis of BiFeO3nanoparticles with enhanced magnetization and promising photocatalytic performance in dye degradation and hydrogen evolution

“… 35 The optical absorption coefficient was obtained by the equation where ε 1 ( ω ) and ε 2 ( ω ) are frequency dependent real and imaginary parts of dielectric function, ω is photon frequency, μ 0 is the permeability of free space. 36 The real part of the dielectric function ε 1 ( ω ) can be evaluated from the imaginary part ε 2 ( ω ) by the famous Kramers–Kronig relationship. 37 Direct optical band gap of the samples was obtained from the equation ( αhν ) n = A ( hν − E opt ), where A is a constant and n denotes the transition type as follows: n = 2 for direct allowed, 2/3 for direct forbidden, 1/2 for indirect allowed and 1/3 for indirect forbidden transitions.…”

“…35 The optical absorption coefficient was obtained by the equation a ¼ ffiffiffiffiffiffiffiffiffiffiffi 2m 0 u p ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi 3 1 2 ðuÞ þ 3 2 2 ðuÞ À 3 1 ðuÞ p q ; where 3 1 (u) and 3 2 (u) are frequency dependent real and imaginary parts of dielectric function, u is photon frequency, m 0 is the permeability of free space. 36 The real part of the dielectric function 3 1 (u) can be evaluated from the imaginary part 3 2 (u) by the famous Kramers-Kronig relationship. 37 Direct optical band gap of the samples was obtained from the equation (ahn) n ¼ A(hn À E opt ), where A is a constant and n denotes the transition type as follows: n ¼ 2 for direct allowed, 2/3 for direct forbidden, 1/2 for indirect allowed and 1/3 for indirect forbidden transitions.…”

“…, where ε 1 (ω) and ε 2 (ω) are frequency dependent real and imaginary parts of dielectric function, ω is photon frequency, μ 0 is the permeability of free space [36]. The real part of the dielectric function ε 1 (ω) can be evaluated from the imaginary part ε 2 (ω) by the famous Kramers-Kronig relationship [37].…”