Electronic and Band Structure calculation of Wurtzite CdS Using GGA and GGA+U functionals

• Published in: Journal of physics. Conference series Vol. 2267; no. 1; pp. 12155 - 12160
• Main Authors: Biswas, Ankan, Meher, S.R., Kaushik, Deepak K.
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.05.2022
• Subjects: Algorithms; Band structure of solids; Bulk modulus; Convergence; Density functional theory; Density of states; Energy gap; Lattice parameters; Mathematical analysis; Optimization; Parameter estimation; Physics; Wurtzite
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/2267/1/012155

Abstract The wurtzite (wz) structure of CdS is analysed using density functional theory within the generalized gradient approximation (GGA) and Hubbard correction (GGA+U). The total energy convergence evaluation is carried out concerning energy cut-off (ecutwfc) and k-point sampling. The geometry optimization of wz-CdS is calculated using the total energy and force minimization process, which is based on the Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimization algorithm. Bulk modulus and lattice parameters are estimated to ensure accuracy of the calculations. The electronic band structure, density of states (DOS), and projected density of states (PDOS) of wz-CdS are analysed. The band structure calculation shows CdS as direct band gap semiconductor. The electronic correlation in CdS is altered by varying U-parameters of valence orbitals of Cd and S. The alteration of electronic correlation results in convergence of the band gap to the experimental value 2.4 eV. The alteration of U-parameter affects substantially the density of states near the band edges.