@conference{
author = "Jelić, Stefan and Novaković, Nikola and Branković, Zorica and Branković, Goran",
year = "2019",
abstract = "A commonly used method for modifying a crystal is doping, where a portion of
lattice positions occupied by an element in a structure is taken up by another element
(dopant). It is therefore important to determine how doping a crystal influences its
stability. Zinc oxide is a semiconductor with wide spectrum of potential application
– LEDs, gas sensors, battery anodes, and even more when doped – changing its
magnetic, electrical or optical properties by doping opens possibility for other
applications like in spintronics.
In order to examine the influence of dopant on stability, we have decided to
observe magnesium-doped zinc oxide in a computational model. Using isovalent
dopant makes the study simpler, and Mg-doped ZnO has been extensively studied in
theory and experiment, which makes it a good basis to compare our findings to
previous studies. We assumed that periodic dopant placement would contribute to
lower energy of the system compared to a random dopant placement, thus we
decided to use a supercell model periodically replicated in 3D space. This approach
can indicate whether formation of superstructures can be expected in experiment
based on enthalpic contribution of the periodically placed dopant. Our model
supercell is made of eight unit cells (2×2×2) with one zinc (6.25 at.%) replaced with
magnesium. Using linearized augmented planewave (LAPW) method in
combination with quantum theory of atoms in molecules (QTAIM), our aim is to
determine energy contribution of a zinc atom in the pure zinc oxide structure and
that of magnesium replacing zinc in the doped supercell in order to show how
doping contributes to stability of the crystal structure. The goal of this combined
approach is to go beyond thermodynamics expressed in terms of simple energy
differences. Using unique and physically meaningful partition of unit cell space it is
possible to calculate various integral contributions (charge density, energy) of
dopant embedded at the particular atomic site. The precise electronic structure is
determined using methods that extend beyond DFT, like LDA+U Hubbard approach
and hybrid functionals for exact description of exchange term in the Hamiltonian of
the system.",
publisher = "Serbian Society for Ceramic Materials",
title = "Novel Approach to Dopant Treatment in Electronic Structure Calculations – a Case Study of Mg-Doped Zinc Oxide",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2309"
}
