Structural phase diagram of LaO1-xFxBiSSe: suppression of the structural phase transition by partial F substitutions

Kazuhisa Hoshi; Shunsuke Sakuragi; Takeshi Yajima; Yosuke Goto; Akira Miura; Chikako Moriyoshi; Yoshihiro Kuroiwa; Yoshikazu Mizuguchi

doi:10.3390/condmat5040081

arXiv · 2006.07798

Structural phase diagram of LaO1-xFxBiSSe: suppression of the structural phase transition by partial F substitutions

Kazuhisa Hoshi·Shunsuke Sakuragi·Takeshi Yajima·Yosuke Goto·Akira Miura·Chikako Moriyoshi·Yoshihiro Kuroiwa·Yoshikazu Mizuguchi

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Abstract

We have investigated low-temperature crystal structure of BiCh2-based compounds LaO1-xFxBiSSe (x = 0, 0.01, 0.02, 0.03, and 0.5), in which anomalous two-fold-symmetric in-plane anisotropy of superconducting states has been observed for x = 0.5. From synchrotron X-ray diffraction experiments, a structural transition from tetragonal to monoclinic was observed for x = 0 and 0.01 at 340 and 240 K, respectively. For x = 0.03, a structural transition and broadening of the diffraction peak were not observed down to 100 K. These facts suggest that the structural transition could be suppressed by 3% F substitution in LaO1-xFxBiSSe. Furthermore, the crystal structure for x = 0.5 at 4 K was examined by low-temperature (laboratory) X-ray diffraction, which confirmed that the tetragonal structure is maintained at 4 K for x = 0.5. Our results suggest that the two-fold-symmetric in-plane anisotropy of superconducting states observed for LaO0.5F0.5BiSSe was not originated from structural symmetry lowering.

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Kazuhisa Hoshi, Shunsuke Sakuragi, Takeshi Yajima, Yosuke Goto, Akira Miura, Chikako Moriyoshi, Yoshihiro Kuroiwa, Yoshikazu Mizuguchi. 2020-06-14. Structural phase diagram of LaO1-xFxBiSSe: suppression of the structural phase transition by partial F substitutions. https://doi.org/10.3390/condmat5040081

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