TY - JOUR
T1 - Pressure-induced collapse of the guest EU off-centering in type-I clathrate EU8Ga16Ge30
AU - Ishimatsu, Naoki
AU - Yokoyama, Kei
AU - Onimaru, Takahiro
AU - Takabatake, Toshiro
AU - Suekuni, Koichiro
AU - Kawamura, Naomi
AU - Tsutsui, Satoshi
AU - Mizumaki, Masaichiro
AU - Ina, Toshiaki
AU - Watanuki, Tetsu
AU - Cuartero, Vera
AU - Mathon, Olivier
AU - Pascarelli, Sakura
AU - Nishibori, Eiji
AU - Irifune, Tetsuo
N1 - Funding Information:
Acknowledgments This study was performed at SPring-8 with the approval of PRC-JASRI (Nos. 2013B1297, 2014B0078, 2015B1253, 2016A1415, and 2017A1296). We acknowledge the ESRF for the provision of beamtime under a scientific collaboration with the BL scientists. This study was partially supported by Grant-in-Aid for Scientific Research on Innovative Areas (Grant Numbers 15H05829, 15H05886), and KAKENHI (15K14170, 15KK0168, 17K05518, 18H01182, 18KK0078). We also acknowledge support from Center for Emergent Condensed-Matter Physics (ECMP), Hiroshima University.
Funding Information:
This study was performed at SPring-8 with the approval of PRC-JASRI (Nos. 2013B1297, 2014B0078, 2015B1253, 2016A1415, and 2017A1296). We acknowledge the ESRF for the provision of beamtime under a scientific collaboration with the BL scientists. This study was partially supported by Grant-in-Aid for Scientific Research on Innovative Areas (Grant Numbers 15H05829, 15H05886), and KAKENHI (15K14170, 15KK0168, 17K05518, 18H01182, 18KK0078). We also acknowledge support from Center for Emergent Condensed-Matter Physics (ECMP), Hiroshima University.
PY - 2019
Y1 - 2019
N2 - We have revealed the pressure-induced collapse of the guest Eu off-centering in type-I clathrate Eu8Ga16Ge30 by the measurements of extended X-ray absorption fine structure (EXAFS) at the Ge K-edge in a temperature range of 10–300 K. Our analysis of the EXAFS spectra at ambient pressure confirmed that the guest Eu is located in the off-centered positions at Δoffset = 0.39(1) Å away from the center of the Ga=Ge tetradodecahedron cage (14-cage). However, with applying pressure to 13.1 GPa, Δoffset decreases to zero, and the atomic density of Eu is concentrated near the center of the 14-cage with a broad distribution. The present result demonstrates a close relationship between Δoffset and the size of the cage: Δoffset decreases when the 14-cage shrinks by applying pressure. With further compression, we have observed a drastic change in the EXAFS spectra due to amorphization. In the amorphous phase, the first nearest neighbor Ge–Ga=Ge bond is longer than in the crystal phase, whereas the guest Eu atom is located randomly with respect to the Ge atoms.
AB - We have revealed the pressure-induced collapse of the guest Eu off-centering in type-I clathrate Eu8Ga16Ge30 by the measurements of extended X-ray absorption fine structure (EXAFS) at the Ge K-edge in a temperature range of 10–300 K. Our analysis of the EXAFS spectra at ambient pressure confirmed that the guest Eu is located in the off-centered positions at Δoffset = 0.39(1) Å away from the center of the Ga=Ge tetradodecahedron cage (14-cage). However, with applying pressure to 13.1 GPa, Δoffset decreases to zero, and the atomic density of Eu is concentrated near the center of the 14-cage with a broad distribution. The present result demonstrates a close relationship between Δoffset and the size of the cage: Δoffset decreases when the 14-cage shrinks by applying pressure. With further compression, we have observed a drastic change in the EXAFS spectra due to amorphization. In the amorphous phase, the first nearest neighbor Ge–Ga=Ge bond is longer than in the crystal phase, whereas the guest Eu atom is located randomly with respect to the Ge atoms.
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U2 - 10.7566/JPSJ.88.114601
DO - 10.7566/JPSJ.88.114601
M3 - Article
AN - SCOPUS:85074750549
VL - 88
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 11
M1 - 114601
ER -