Optoelectronic Response of GeZn2O4 through the Modified Becke–Johnson Potential
Iftikhar Ahmad1, B. Amin2*, M. Maqbool3, S. Muhammad2, G. Murtaza4, S. Ali5, N. A. Noor5
1Department of Physics, University of Malakand, Pakistan 2Materials Modeling Lab, Department of Physics, Hazara University, 21300, Pakistan 3Department of Physics and Astronomy, Ball State University, Indiana, 47306-0505, USA 4Department of Physics, Islamia College University, Peshawar, Pakistan 5Department of Physics, University of the Punjab, Quaid-e-Azam Campus, 54590, Pakistan
Abstract:A first-principles technique capable of describing the nearly excited states of semiconductors and insulators, namely the modified Becke–Johnson (mBJ) potential approximation, is used to investigate the electronic band structure and optical properties of spinel oxides: GeZn2O4. The predicted band gaps using the mBJ approximation are significantly more accurate than the proposed previous theoretical work using the common LDA and GGA. Band gap dependent optical parameters, like the dielectric constant, index of refraction, reflectivity and optical conductivity are calculated and analyzed. The results from the dielectric constant shows that the numerical value of the static dielectric, after dropping constantly, becomes less than zero and the material exhibits metallic behavior. The refractive index also drops below unity for photons higher than 18 eV, which indicates that the velocities of incident photons are greater than the velocity of light. However, these phenomena can be explained by the fact that a signal must be transmitted as a wave packet rather than a monochromatic wave. This comprehensive theoretical study of the optoelectronic properties predicts that these materials can effectively be used in optical devices.
. [J]. 中国物理快报, 2012, 29(9): 97102-097102.
Iftikhar Ahmad, B. Amin, M. Maqbool, S. Muhammad, G. Murtaza, S. Ali, N. A. Noor. Optoelectronic Response of GeZn2O4 through the Modified Becke–Johnson Potential. Chin. Phys. Lett., 2012, 29(9): 97102-097102.