TY  - JOUR
AU  - Hensling, Felix V. E.
AU  - Dahliah, Diana
AU  - Dulal, Prabin
AU  - Singleton, Patrick
AU  - Sun, Jiaxin
AU  - Schubert, Jürgen
AU  - Paik, Hanjong
AU  - Subedi, Indra
AU  - Subedi, Biwas
AU  - Rignanese, Gian-Marco
AU  - Podraza, Nikolas J.
AU  - Hautier, Geoffroy
AU  - Schlom, Darrell G.
TI  - Epitaxial stannate pyrochlore thin films: Limitations of cation stoichiometry and electron doping
JO  - APL materials
VL  - 9
IS  - 5
SN  - 2166-532X
CY  - Melville, NY
PB  - AIP Publ.
M1  - FZJ-2021-04860
SP  - 051113 -
PY  - 2021
AB  - We have studied the growth of epitaxial films of stannate pyrochlores with a general formula A 2 Sn 2 O 7 (A = La and Y) and find that itis possible to incorporate ∼ 25% excess of the A-site constituent; in contrast, any tin excess is expelled. We unravel the defect chemistry,allowing for the incorporation of excess A-site species and the mechanism behind the tin expulsion. An A-site surplus is manifested by ashift in the film diffraction peaks, and the expulsion of tin is apparent from the surface morphology of the film. In an attempt to increaseLa 2 Sn 2 O 7 conductivity through n-type doping, substantial quantities of tin have been substituted by antimony while maintaining good filmquality. The sample remained insulating as explained by first-principles computations, showing that both the oxygen vacancy and antimony-on-tin substitutional defects are deep. Similar conclusions are drawn on Y 2 Sn 2 O 7 . An alternative n-type dopant, fluorine on oxygen, is shallowaccording to computations and more likely to lead to electrical conductivity. The bandgaps of stoichiometric La 2 Sn 2 O 7 and Y 2 Sn 2 O 7 filmswere determined by spectroscopic ellipsometry to be 4.2 eV and 4.48 eV, respectively.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000705895700002
DO  - DOI:10.1063/5.0049334
UR  - https://juser.fz-juelich.de/record/903136
ER  -