Zhang Liping, Kang Chaoyang, Liu Chengyan, Wang Kai, Zhang Weifeng
School of Future Technology, Henan University Zhengzhou 450046 China
Center for Topological Functional Materials, Henan University Kaifeng 475004 China
RSC Adv. 2023 Aug 31;13(37):25797-25803. doi: 10.1039/d3ra02701e. eCollection 2023 Aug 29.
High-quality BiSrCaCuO superconducting thin films are successfully grown on a SrTiO substrate by the Pulsed Laser Deposition technique. Superconducting critical transition temperatures have reached up to 85 K by using optimized growth parameters. In addition, we demonstrated the two-dimensional nature of the superconductivity of thin films by virtue of exhibiting Berezinskii-Kosterlitz-Thouless (BKT) physics and anisotropic magnetic response. Furthermore, three distinct regimes are identified based on the analysis of direct current resistance. The non-Fermi liquid phase and BKT phase fluctuation zone almost perfectly merge together, which implies that the system undergoes a unique topological state that is determined by the BKT phase fluctuation preceding the onset of the superconducting state. The emergence of such a topological state radically differentiates from the three-dimensional superconducting transition, which spontaneously breaks the gauge symmetry. The current studies on the BiSrCaCuO superconducting thin films provide some new insights for understanding the rich quantum states of matter that emerge in the vicinity of the superconducting phase transition and highlight the significant role of BKT fluctuation on two-dimensional superconducting transition.
通过脉冲激光沉积技术，在SrTiO衬底上成功生长出高质量的BiSrCaCuO超导薄膜。利用优化的生长参数，超导临界转变温度已达到85K。此外，我们通过展示 Berezinskii-Kosterlitz-Thouless（BKT）物理特性和各向异性磁响应，证明了薄膜超导的二维特性。此外，基于直流电阻分析确定了三个不同的区域。非费米液相和BKT相波动区几乎完美融合在一起，这意味着该系统经历了一种独特的拓扑状态，该状态由超导态开始之前的BKT相波动决定。这种拓扑状态的出现与三维超导转变有根本区别，三维超导转变会自发打破规范对称性。目前对BiSrCaCuO超导薄膜的研究为理解超导相变附近出现的丰富量子态物质提供了一些新见解，并突出了BKT波动在二维超导转变中的重要作用。
