PC-2-4
Pressure-induced superconductivity and isosymmetric structural transition in quasi-one-dimensional Pd based ternary chalcogenide
14:30-14:45 28/11/2023
*Wenhui Liu1, Jiajia Feng1,3, Sheng Li1,2,4, Zhixiang Shi1,4
1. School of Physics, Southeast University, Nanjing 211189, China
2. Purple Mountain Laboratories, Nanjing 211111, China
3. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
4. Key Laboratory of Quantum Materials and Devices of Ministry of Education School of Physics, Southeast University, Nanjing 211189, China
Finding and studying the topological structure and electronic properties of superconductors with quasi-one-dimensional(q-1D) structure is very important to understand the new superconducting mechanism, and it is also an important method to explore Majorana fermions[1-3]. Here, we report a thorough study of superconductivity and phase transition in a quasihydrostatically pressurized q-1D Pd based ternary chalcogenide by electrical transport, in situ x-ray diffraction (XRD), Raman spectroscopy, and density functional calculation. We find a pressure-induced semiconductor-metal where valence bands cross the Fermi level to form a set of small hole pockets at P~ 3 .7 GPa. The pressure-induced superconductivity with lowering temperature, accompanied by a monoclinic distortion at the critical pressure Pc ~ 30.8 GPa, with the slope of Rxy (H) switches from positive to negative. Both XRD measurements and theoretical calculations provide evidence that this structural transition is determined to be isosymmetric, mainly resulting from rearrangement of the S atoms along the a and c axis, indicative of the importance of electron–lattice coupling. When the pressure increases to 82 GPa, the high pressure phase has a very high density of electron states at the Fermi level with Tconset~ 5.2 K, likely mediated by strongly electron-coupled phonons. We hope that the results obtained in this study will stimulate the effort to explore pressure induced superconductivity in the quasi-1D ternary chalcogenide family.
1. Gooth J, Bradlyn B, Honnali S, et al., Axionic charge-density wave in the Weyl semimetal (TaSe4)2I. Nature, 2019, 575(7782): 315-319.
2. Li X, Chen D, Jin M, et al., Pressure-induced phase transitions and superconductivity in a quasi–1-dimensional topological crystalline insulator α-Bi4Br4. Proc. Natl. Acad. Sci., 2019, 116(36): 17696-17700.
3. Kitaev, A. Yu., Unpaired Majorana fermions in quantum wires. Phys.-Usp., 2001, 44.10S: 131.
This work was partly supported by the National Natural Science Foundation of China (Grants No. U1932217), the National Key R&D Program of China (Grant No. 2018YFA0704300), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB25000000) and the open research fund of Key Laboratory of Quantum Materials and Devices (Southeast University), Ministry of Education. This work was performed at the 4W2 HP-Station of BSRF, Institute of High Energy Physics, which is supported by the Chinese Academy of Sciences. We thank the Big Data Computing Center of Southeast University for providing the facility support on the numerical calculations in this paper.
