1. Investigations of key issues on the reproducibility of high-Tc superconductivity emerging from compressed La3Ni2O7
- Author
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Zhou, Yazhou, Guo, Jing, Cai, Shu, Sun, Hualei, Wang, Pengyu, Zhao, Jinyu, Han, Jinyu, Chen, Xintian, Chen, Yongjin, Wu, Qi, Ding, Yang, Xiang, Tao, Mao, Ho-kwang, and Sun, Liling
- Subjects
Condensed Matter - Superconductivity - Abstract
Recently, the signatures of superconductivity near 80 K have been discovered in the single crystal of La3Ni2O7 under pressure and thus has attracted significant attention. However, there are several critical issues that have been perplexing the scientific community. These include (1) what factors contribute to the poor reproducibility of the experimental results, (2) what the intrinsic nature of the pressure-induced superconductivity is, bulk or filamentary, (3) where the superconducting phase locates within the sample if it is indeed filamentary, and (4) what the oxygen content is necessary for the development and stabilization of superconductivity. In this study, we employ comprehensive high-pressure measurements to address these crucial issues. By demonstrating both zero resistance and diamagnetism, we are the first to confirm the existence of high-temperature superconductivity in La3Ni2O7. Through our sensitive ac susceptibility measurements, we are the first to quantify the superconducting volume fraction in La3Ni2O7 at the level of 1%. In tandem with our observation of the anisotropic zero-resistance state only in some of the samples, we suggest that the superconductivity in this nickelate is filamentary-like. By our scanning transmission electron microscopy (STEM) investigations, we propose that the filamentary superconductivity most likely emerges at the interface between the La3Ni2O7 and La4Ni3O10 phases. Further, the upper and lower bounds of the oxygen content required for the presence of superconductivity were determined. Our results provide not only new insights into understanding the puzzling issues in this material, but also significant information for achieving a better understanding on the superconductivity of this material., Comment: 25 pages, 4 figures
- Published
- 2023