# Exploring Symmetry-Independent Configurations in KTa0.5Nb0.5O3 Solid Solutions: A First-Principles, QTAIM, and AIMD Approach

## TL;DR

This study explores different atomic arrangements in a lead-free material to understand how they affect its electronic and bonding properties for potential use in electro-optic and dielectric technologies.

## Contribution

The paper systematically investigates all symmetry-independent configurations in KTa0.5Nb0.5O3 using first-principles and AIMD methods.

## Key findings

- Low-energy atomic arrangements were identified through configurational energy analysis.
- B-site ordering significantly modulates the electronic structure and bonding characteristics.
- AIMD simulations confirmed the stability of low-energy models at finite temperatures.

## Abstract

Potassium tantaloniobate (KTN) is a lead-free perovskite
solid
solution with promising electro-optic, ferroelectric, and dielectric
applications. Here, we present a systematic first-principles study
of KTa0.5Nb0.5O3, exploring all 21
symmetry-independent configurations (SICs) in 2 × 2 × 2
cubic and tetragonal supercells. Configurational energy analysis identifies
the most stable atomic arrangements, which are further characterized
through band structure, density of states, and quantum theory of atoms
in molecules (QTAIM) descriptors. Ab initio molecular dynamics (AIMD)
simulations at finite temperature confirm the dynamical robustness
of low-energy models and highlight subtle symmetry-dependent fluctuations.
The results demonstrate how B-site ordering modulates electronic structure
and bonding, offering guidance for the design of compositionally engineered
perovskites for electro-optic and dielectric technologies.