eprintid: 10204978
rev_number: 7
eprint_status: archive
userid: 699
dir: disk0/10/20/49/78
datestamp: 2025-02-19 09:56:09
lastmod: 2025-02-19 09:56:09
status_changed: 2025-02-19 09:56:09
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Liu, T
creators_name: Zhang, X
creators_name: Guan, J
creators_name: Chen, X
creators_name: Lu, Y
creators_name: Keal, TW
creators_name: Buckeridge, J
creators_name: Catlow, CRA
creators_name: Sokol, AA
title: Origins of intrinsic p-type conductivity, p-n transition and substoichiometry in SrO
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F56
note: This article is licensed under a Creative Commons Attribution 3.0 Unported Licence
abstract: To understand the complex electrical behaviour and deviations from ideal stoichiometry in strontium oxide we have investigated its defect chemistry using a hybrid quantum mechanical/molecular mechanical (QM/MM) embedded-cluster approach. Depending on the temperature and oxygen partial pressure, oxygen interstitials or strontium and oxygen vacancies are found to dominate, while strontium interstitials are rare. Notably, charge-neutral oxygen interstitials form a peroxy-like closed-shell configuration, which is the commonest native point defect in SrO under normal conditions explaining the Sr substoichiometry which is not electrically active. Formally charged double acceptors strontium vacancies prove to be the primary source of the hole excess over negative carriers supplied by donor species, contributing to the material's p-type conductivity. Based on our calculations, we predict that at ultralow oxygen partial pressure (P = 1.0 × 10−15 bar) and high temperatures (>1100 K) in SrO, the electron concentration surpasses the hole concentration, which has previously been reported in pure BaO (also at about 1100 K) and the double barium-strontium oxide (at 850 K) by D. W. Wright, (Nature, 1949, 4173, 714) with the oxygen split interstitial acting as a donor. On increasing the oxygen partial pressure, the hole concentration exceeds the electron concentration, resulting in effective p-type conductivity. Only under low oxygen pressures (e.g., 10−8 bar) and high extrinsic donor concentrations (>1017 cm−3) might SrO switch to n-type conductivity at high temperatures (>1250 K). This study provides essential insights into intrinsic defects and mechanisms of SrO's p-type conductivity, aiding in understanding and predicting other p-type materials.
date: 2025-01-01
date_type: published
publisher: Royal Society of Chemistry (RSC)
official_url: https://doi.org/10.1039/d4ta07690g
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2361741
doi: 10.1039/d4ta07690g
lyricists_name: Catlow, Charles
lyricists_name: Sokols, Alekseys
lyricists_name: Guan, Jingcheng
lyricists_id: CRACA43
lyricists_id: AASOK81
lyricists_id: JGUAN43
actors_name: Catlow, Charles
actors_id: CRACA43
actors_role: owner
full_text_status: public
publication: Journal of Materials Chemistry A
issn: 2050-7488
citation:        Liu, T;    Zhang, X;    Guan, J;    Chen, X;    Lu, Y;    Keal, TW;    Buckeridge, J;         ... Sokol, AA; + view all <#>        Liu, T;  Zhang, X;  Guan, J;  Chen, X;  Lu, Y;  Keal, TW;  Buckeridge, J;  Catlow, CRA;  Sokol, AA;   - view fewer <#>    (2025)    Origins of intrinsic p-type conductivity, p-n transition and substoichiometry in SrO.                   Journal of Materials Chemistry A        10.1039/d4ta07690g <https://doi.org/10.1039/d4ta07690g>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10204978/1/d4ta07690g.pdf