PCP2-3
Pressure effects on superconducting phases of Eu2SrBi2Se2F4
13:15-14:45 Dec.4
*Kento Ishigaki1, Jun Gouchi2, Kiyoshi Torizuka2, Sonachalam Arumugam3, Ashok Kumar Ganguli4,5, Zeba Haque5,6, Ganesan Kalaiselven3, Gohil Singh Thakur4, Yoshiya Uwatoko2
Department of Applied Physics, Tokyo University of Science, Tokyo 125-8585, Japan1
The Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581, Japan2
Centre for High Pressure Research Department of Physics, Bharathidasan University, Tamil Nadu 620-024, India3
Department of Chemical Sciences, Indian Institute of Science Education & Research, Berhampur, Odisha 760-003, India4
Department of Chemistry, Indian Institute of Technology, Delhi 110-016, India5
Department of Chemistry, Jamia Millia Islamia, Delhi 110-025, India6
Eu3-xSrxBi2S4F4 (x = 0, 1 and 2) are classified as a group of BiS2-based superconductors [1,2]. Eu3Bi2S4F4 and Eu2SrBi2S4F4 exhibit superconductivity through self-doping with Eu-valence fluctuation [1, 3]. The superconducting transition temperature (Tc) is observed at 1.5 and 0.8 K for Eu3Bi2S4F4 and Eu2SrBi2S4F4 respectively. It has been demonstrated that Tc increases with the application of external pressure and/or chemical pressure [4-7]. The Eu3-xSrxBi2S4-ySeyF4 compound exhibits a tetragonal structure (space group: I4 / mmm) and Tc is nearly 3 K [7]. Upon application of pressure, its Tc increases continuously up to approximately 3 GPa [8]. In contrast, the pressure dependence of Tc in Eu2SrBi2S2.5Se1.5F4 is complex accompanied by structural phase transitions up to 12 GPa [9]. In order to confirm the physical properties of Eu2SrBi2S2Se2F4, we have measured the electrical resistivity and X-ray diffraction patterns (XRD) of this material above 10 GPa in the present study.
Figure 1 shows the pressure dependence of Tc in Eu2SrBi2S2Se2F4. Two peaks were observed in Tc at 2.62 K (at 1.5 GPa) and 2.61 K (at 5 GPa). Figure 2 presents the XRD patterns of Eu2SrBi2S2Se2F4 under high-pressure. At 4.88 GPa, the appearance of new peaks indicated by arrows suggests the occurrence of a structural phase transition. Therefore, it can be concluded that Eu2SrBi2S2Se2F4 should exhibit multiple superconducting phases up to 5 GPa.
In this paper, the properties of the superconducting phases, focusing on the temperature dependence of resistivity and X-ray diffraction patterns under high-pressure.
[1] H. F. Zhai et al. J. Am. Chem. Soc. 136 15386 (2014).
[2] Z. Haque et al. Inorg. Chem. 56 3182 (2017).
[3] Z. Haque et al. Mater. Today Proc. 36 743 (2021).
[4] Y. Luo et al. Phys. Rev. B 90 220510 (2014).
[5] K. Ishigaki et al. JPS Conf. Proc. 30, 011058 (2020).
[6] P. Zhang et al. Europhys. Lett. 111 27002 (2015).
[7] Z. Haque et al. Inorg. Chem. 57 37 (2018).
[8] N. Subbulakshmi et al. J. Supercond. Nov. Magn. 32 2359 (2019).
[9] K. Ishigaki et al. J. Phys. Soc. Jpn, 93, 024706 (2024).
This work was supported by JSPS KAKENHI Grant Number JP19H00648. Prof. L. C. Gupta is acknowledged for his initial contributions to the work on these and other similar materials while he was a visiting scientist at the Dept. of Chemistry, IIT, Delhi.
Keywords: BiS2-based superconductor, High-pressure, Structural phase transition