# The inequivalent substitution on Ca site of cubic CaTiO3 perovskite for transparent conductive oxides from USPEX and DFT

## TL;DR

This study uses USPEX and DFT to explore how substituting Ca in CaTiO3 affects its electronic properties, aiming to develop p- and n-type transparent conductive oxides with stable structures.

## Contribution

It demonstrates the use of genetic algorithms and DFT to predict stable structures and electronic properties of CaTiO3 with various substitutions for TCO applications.

## Key findings

- Na substitution induces p-type behavior without oxygen vacancies.
- Al substitution results in n-type conductivity with tetragonal phase.
- p-type Ca0.75Na0.25TiO3 shows higher mobility than n-type.

## Abstract

Based on genetic evolution algorithm, universal structure predictor USPEX assists to explore the most stable structure from Na+ substituting Ca2+ under variable concentration, for p type transparent conductive oxide application. The study finds 2 atoms of NaCa maintain the octahedral packing and cubic phase without the presence of oxygen vacancy, but the electron loss causes in fermi level entering into valence band, realizing p type TCOs character. While others still remain insulator character due to the compensation of oxygen vacancy. Applying Al3+ substituting Ca2+ achieve the fermi level into conduction band with n-type TCOs, with the symmetry of tetragonal phase. And the transport properties for p- type Ca0.75Na0.25TiO3 and n-type Ca0.75Al0.25TiO3 are calculated, the mobility in p- type Ca0.75Na0.25TiO3 is more superior owing to its curvature edge.

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Source: https://tomesphere.com/paper/1905.00548