TY - JOUR
T1 - Superconductivity in topological insulator β-PdBi2 under pressure
AU - Suzuki, Ai
AU - Taguchi, Tomoya
AU - Li, Huan
AU - Wang, Yanan
AU - Ishii, Hirofumi
AU - Liao, Yen Fa
AU - Goto, Hidenori
AU - Eguchi, Ritsuko
AU - Kubozono, Yoshihiro
N1 - Funding Information:
This study was partly supported by Grants-in-Aid (17K05500, 18K04940, 18K18736, 19H02676, 20H05878 and 20H05879) from MEXT, and by the Program for Promoting the Enhancement of Research Universities. The XRD measurements at SPring-8 were supported by 2018B4140 and 2019A4131.
Publisher Copyright:
© 2021 IOP Publishing Ltd Printed in the UK
PY - 2021/3/31
Y1 - 2021/3/31
N2 - The topological insulator PdBi2 exhibits two different crystal phases at ambient pressure, i.e., ‘α-PdBi2’ and ‘-PdBi2’. The pressure dependence of crystal structure and superconductivity of α-PdBi2 has been fully elucidated thus far. However, the physical properties of β-PdBi2 crystals under pressure have not been sufficiently investigated. In this study, we fully investigate the crystal structure and superconductivity of β-PdBi2 under pressure based on synchrotron x-ray diffraction (XRD) patterns. The temperature dependence of β-PdBi2 indicates its superconductivity with a superconducting transition temperature (Tc) as high as 4.10 K, and its crystal structure is tetragonal [space group of I4/mmm (no. 139)]. The XRD patterns at 0–22.0 GPa indicate no structural phase transitions, and the unit cell volume shrinks monotonically with pressure, unlike the behavior of α-PdBi2. Furthermore, α-PdBi2 transformed to β-PdBi2 under pressure. This suggests that β-PdBi2 is stable under pressure. The superconductivity is clearly observed at 0–11.8 GPa, and the value of Tc is almost constant at ∼4.4 K. The temperature dependence of the upper critical field at ambient pressure and 10.7 GPa indicates that the superconductivity is not attributed to a simple s-wave dirty limit but an s-wave clean or p-wave polar model. This is the first systematic study of superconductivity of topological insulator β-PdBi2 under pressure.
AB - The topological insulator PdBi2 exhibits two different crystal phases at ambient pressure, i.e., ‘α-PdBi2’ and ‘-PdBi2’. The pressure dependence of crystal structure and superconductivity of α-PdBi2 has been fully elucidated thus far. However, the physical properties of β-PdBi2 crystals under pressure have not been sufficiently investigated. In this study, we fully investigate the crystal structure and superconductivity of β-PdBi2 under pressure based on synchrotron x-ray diffraction (XRD) patterns. The temperature dependence of β-PdBi2 indicates its superconductivity with a superconducting transition temperature (Tc) as high as 4.10 K, and its crystal structure is tetragonal [space group of I4/mmm (no. 139)]. The XRD patterns at 0–22.0 GPa indicate no structural phase transitions, and the unit cell volume shrinks monotonically with pressure, unlike the behavior of α-PdBi2. Furthermore, α-PdBi2 transformed to β-PdBi2 under pressure. This suggests that β-PdBi2 is stable under pressure. The superconductivity is clearly observed at 0–11.8 GPa, and the value of Tc is almost constant at ∼4.4 K. The temperature dependence of the upper critical field at ambient pressure and 10.7 GPa indicates that the superconductivity is not attributed to a simple s-wave dirty limit but an s-wave clean or p-wave polar model. This is the first systematic study of superconductivity of topological insulator β-PdBi2 under pressure.
KW - Crystal structure
KW - Electrical resistance
KW - Pressure
KW - Superconductivity
KW - Topological insulator
UR - http://www.scopus.com/inward/record.url?scp=85101002722&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85101002722&partnerID=8YFLogxK
U2 - 10.1088/1361-648X/abd99c
DO - 10.1088/1361-648X/abd99c
M3 - Article
AN - SCOPUS:85101002722
VL - 33
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
SN - 0953-8984
IS - 13
M1 - 135702
ER -