Superconductivity in unconventional metals

作者：Zhilong Yang, Haohao Sheng, Zhaopeng Guo, Ruihan Zhang, Quansheng Wu, H. Weng, Zhongyuan Fang, Zhijun Wang · 发表于：npj Computational Materials · 年份：2023 · DOI：10.1038/s41524-024-01210-z · 被引用次数：13 · 研究领域：Physics

Based on first-principles calculations, we demonstrate that 1H/2H-phase transition metal dichalcogenides M X _2 ( M  = Nb, Ta;  X  = S, Se, Te) are unconventional metals, which have an empty-site band of $${A}_{1}^{{\prime} }@1e$$ A 1 ′ @ 1 e elementary band representation at the Fermi level. The computed phonon dispersions indicate the stability of the system at high temperatures, while the presence of the soft phonon mode suggests a phase transition to the charge density wave state at low temperatures. Based on the Bardeen-Cooper-Schrieffer theory and computed electron-phonon coupling, our calculations show that the superconductivity (SC) in NbSe_2 is mainly attributed to the soft phonon mode due to the half filling of the empty-site band. Accordingly, the SC has been predicted in unconventional metals TaNS monolayer and 2H-TaN_2 bulk with computed T _ C  = 10 K and 26 K respectively. These results demonstrate that the unconventional metals with partial filling of the empty-site band offer an attractive platform to search for superconductors.