Neutral defects in SrTiO3 studied with screened hybrid density functional theory
Fedwa El-Mellouhi1, Edward N Brothers, Melissa J Lucero
1Chemistry Department, Texas A&M University at Qatar, Education City, Doha, Qatar. fadwa.el mellouhi@qatar.tamu.edu
Summary
Neutral defects in strontium titanate (SrTiO3) were studied. Oxygen vacancies cause lattice changes, impacting electron mobility and defect band positions for experimental comparison.
Area of Science:
- Materials Science
- Solid-State Physics
- Computational Materials Science
Background:
- Strontium titanate (SrTiO3) is a key material in electronics.
- Understanding neutral defects is crucial for optimizing SrTiO3 properties.
- Previous studies have not fully characterized defect behavior and its impact on electronic properties.
Purpose of the Study:
- To calculate the properties of neutral defects in SrTiO3.
- To investigate the effect of oxygen vacancies on SrTiO3 lattice and electronic structure.
- To provide reliable predictions for experimental validation.
Main Methods:
- Screened hybrid density functional (Heyd, Scuseria, and Ernzerhof) calculations.
- Analysis of formation energies, crystal field splittings, and relaxation geometries.
- Estimation of defect band positions within the SrTiO3 band gap.
Main Results:
- Oxygen vacancies induce tetragonal elongation along the z-axis.
- Electron effective masses at the conduction band minimum deviate from bulk values.
- Defect bands are located within the SrTiO3 gap without post hoc corrections.
Conclusions:
- Calculated defect properties offer a reliable basis for experimental comparison.
- Lattice distortions around oxygen vacancies influence electron mobility.
- The findings contribute to the understanding and application of SrTiO3 in electronic devices.
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