TY - JOUR
T1 - Structure determination in thin film B a1-x L ax F e2 A s2
T2 - Relation between the FeA s4 geometry and superconductivity
AU - Kobayashi, Kensuke
AU - Nakao, Akiko
AU - Maki, Sachiko
AU - Yamaura, Jun Ichi
AU - Katase, Takayoshi
AU - Sato, Hikaru
AU - Sagayama, Hajime
AU - Kumai, Reiji
AU - Kuramoto, Yoshio
AU - Murakami, Youichi
AU - Hiramatsu, Hidenori
AU - Hosono, Hideo
N1 - Funding Information:
This work was supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) through the Element Strategy Initiative to Form Core Research Center and by the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grants No. 16K05434 and No. 17H01318), a JSPS Grant-in-Aid for Scientific Research on Innovative Areas “Nano Informatics” (Grant No. 25106007), and Support for Tokyotech Advanced Research (STAR). The XRD study was performed with the approval of the Photon Factory Program Advisory Committee (Proposals No. 2013S2-002, No. 2016S2-004, No. 2014V002, and No. 2015V002).
Publisher Copyright:
© 2017 American Physical Society.
PY - 2017/9/11
Y1 - 2017/9/11
N2 - A thin film superconductor Ba1-xLaxFe2As2 is the first electron-doped compound of BaFe2As2 obtained by the substitution of Ba with La within a blocking layer. By contrast, in conventional electron-doped Ba(Fe1-xCox)2As2, the dopant (Co) is inserted into the conduction layer. The different shapes, or geometries, of FeAs4 are expected in the two compounds above. However, the structure of Ba1-xLaxFe2As2 is investigated here because of being a thin film. To clarify the effect of the geometry, we make use of an up-to-date method to determine the atomic positions of the Ba1-xLaxFe2As2 thin film using synchrotron x-ray diffraction. We established that the FeAs4 geometry in Ba1-xLaxFe2As2 indicates a systematic variation upon doping, which is opposite to that in Ba(Fe1-xCox)2As2. However, the superconducting transition temperatures nearly coincide with each other for the same amount of dopings. The present result contrasts with a suggestion that the FeAs4 geometry strongly influences the superconductivity in iron pnictides. Hence, we propose that the carrier density is the more important parameter than the FeAs4 geometry and that the electronic correlation plays a significant role in the superconductivity for the electron-doped BaFe2As2.
AB - A thin film superconductor Ba1-xLaxFe2As2 is the first electron-doped compound of BaFe2As2 obtained by the substitution of Ba with La within a blocking layer. By contrast, in conventional electron-doped Ba(Fe1-xCox)2As2, the dopant (Co) is inserted into the conduction layer. The different shapes, or geometries, of FeAs4 are expected in the two compounds above. However, the structure of Ba1-xLaxFe2As2 is investigated here because of being a thin film. To clarify the effect of the geometry, we make use of an up-to-date method to determine the atomic positions of the Ba1-xLaxFe2As2 thin film using synchrotron x-ray diffraction. We established that the FeAs4 geometry in Ba1-xLaxFe2As2 indicates a systematic variation upon doping, which is opposite to that in Ba(Fe1-xCox)2As2. However, the superconducting transition temperatures nearly coincide with each other for the same amount of dopings. The present result contrasts with a suggestion that the FeAs4 geometry strongly influences the superconductivity in iron pnictides. Hence, we propose that the carrier density is the more important parameter than the FeAs4 geometry and that the electronic correlation plays a significant role in the superconductivity for the electron-doped BaFe2As2.
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U2 - 10.1103/PhysRevB.96.125116
DO - 10.1103/PhysRevB.96.125116
M3 - Article
AN - SCOPUS:85030170087
VL - 96
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 12
M1 - 125116
ER -