Related Experiment Video
Updated: Feb 5, 2026

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis
Published on: May 10, 2021
Dopant distributions and band-edge positions in Sr-doped NaTaO3: a first-principles study
Ryusei Morimoto1, Hiroki Uratani1,2, Hiroshi Onishi3,4,5
1Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan. uratani@moleng.kyoto-u.ac.jp.
None:
Sr doping is known to enhance the water-splitting activity of NaTaO3 photocatalysts and is often accompanied by surface segregation of Sr, yet, the electronic-structural origin remains unclear. Here, we employ first-principles calculations with explicit enumeration of all Sr configurations in bulk NaTaO3 (NTO) and TaO2-terminated (001) surfaces. In the bulk, the enumeration shows that shorter Sr-Sr separations are energetically preferred. At surfaces, Sr segregates and accumulates strongly. Layer-resolved local density of states indicates that in-gap states are confined to the outermost TaO2 layer, while interior layers retain a near-bulk gap. In Sr-rich surface layers, both band edges shift upward relative to the interior. Population analyses link the valence-band rise to O-O contraction and the conduction-band rise to Ta-Ta elongation. Sr-doping and segregation yields near-surface band bending and a built-in electric field that can promote electron-hole separation and suppress recombination, rationalising the observed activity gains.
More Related Videos
Related Concept Videos
Band Theory
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
The Uncertainty Principle
The Pauli Exclusion Principle
The Aufbau Principle and Hund's Rule
Hardy-Weinberg Principle
Energy Bands in Solids
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...

