van der Waals Self-Epitaxial Growth of Inch-Sized Superconducting Niobium Diselenide Films.

Ma, Liang; Wang, Xiaohan; Wang, Hao; Wang, Xiangyi; Zou, Guifu; Guan, Yanqiu; Guo, Shuya; Li, Haochen et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

Ultrathin superconducting films are the basis of superconductor devices. van der Waals (vdW) NbSe<sub>2</sub> with noncentrosymmetry exhibits exotic superconductivity and shows promise in superconductor electronic devices. However, the growth of inch-scale NbSe<sub>2</sub> films with layer regulation remains a challenge because vdW structural material growth is strongly dependent on the epitaxial guidance of the substrate. Herein, a vdW self-epitaxy strategy is developed to eliminate the substrate driving force in film growth and realize inch-sized NbSe<sub>2</sub> film growth with thicknesses from 2.1 to 12.1 nm on arbitrary substrates. The superconducting transition temperature of 5.1 K and superconducting transition width of 0.30 K prove the top homogeneity and quality of superconductivity among all of the synthetic NbSe<sub>2</sub> films. Coupled with a large area and substrate compatibility, this work paves the way for developing NbSe<sub>2</sub> superconductor electronics.