Choi, Heechae Song, Jin Dong Lee, Kwang-Ryeol Kim, Seungchul 2024-01-20T07:04:41Z 2024-01-20T07:04:41Z 2021-09-05 2015-04-20 0020-1669 https://pubs.kist.re.kr/handle/201004/125538 The visible-light absorption and luminescence of wide band gap (3.25 eV) strontium titanate (SrTiO3) are well-known, in many cases, to originate from the existence of natural oxygen deficiency in the material. In this study based on density functional theory (DFT) calculations, we provide, to the best of our knowledge, the first report indicating that oxygen vacancies in the bulk and on the surfaces of SrTiO3 (STO) play different roles in the optical and magnetic properties. We found that the doubly charged state of oxygen vacancy (V-O(2+)) is dominant in bulk SrTiO3 and does not contribute to the sub-band gap photoexcitation or intrinsic magnetism of STO. Neutral oxygen vacancies (V-O(0)) on (001) surfaces terminated with both TiO2 and SrO layers induce magnetic moments, which are dependent on the charged state of VO. The calculated absorption spectra for the (001) surfaces exhibit mid-infrared absorption (<0.5 eV) and sub-band gap absorption (2.5-3.1 eV) due to oxygen vacancies. In particular, V-O(0) on the TiO2-terminated surface has a relatively low formation energy and magnetic moments, which can explain the recently observed spin-dependent photon absorptions of STO in a magnetic circular dichroism measurement [Rice, W. D.; et al. Nat. Mater.13, 481, 2014]. English AMER CHEMICAL SOC OPTICAL-PROPERTIES ROOM-TEMPERATURE DOPED IN2O3 ROLES PHOTOLUMINESCENCE NONSTOICHIOMETRY FERROMAGNETISM Correlated Visible-Light Absorption and Intrinsic Magnetism of SrTiO3 Due to Oxygen Deficiency: Bulk or Surface Effect? Article 10.1021/ic502905m 1 INORGANIC CHEMISTRY, v.54, no.8, pp.3759 - 3765 INORGANIC CHEMISTRY 54 8 3759 3765 scie scopus 000353429500009 2-s2.0-84928345023 Chemistry, Inorganic & Nuclear Chemistry Article OPTICAL-PROPERTIES ROOM-TEMPERATURE DOPED IN2O3 ROLES PHOTOLUMINESCENCE NONSTOICHIOMETRY FERROMAGNETISM Density Functional Theory First-principles calculations SrTiO3 Oxygen vacancy surface defects magnetism