The Study of Effects of Strain on Band Gap of Perovskite Crystal using LDA and LDA+U Method

Master's Thesis from the year 2017 in the subject Physics - Nuclear Physics, grade: 90, Tribhuvan University (Goldengate International College, Battisputali, Kathmandu), language: English, abstract: Calcium Titanate (CaTiO3) is a ceramic material having simple cubic crystal with perovskite structure. It is a diamagnetic colourless solid but appears coloured due to the presence of impurities. This materal can be used for semiconductor, laser, microwave, biochemical applications and photovoltanics.

We have performed density functional theory (DFT) to study the optimized geometric structure, local density approximation (LDA) and local density approximation using Hubbard potential(U)(LDA+U) to study the effect of strain on the atomic displacement of Oxygen and Titanium atoms, band gap and partial density of states (PDOS). The band gap obtained during our present work is in close approximation with the experimental band gap indicating CaTiO3 is an insulator with indirect band gap.