We report on the growth and characterization of a niobium titanium nitride (NbTiN) film on a Si substrate prepared by ultrahigh vacuum sputtering. We show that the superconducting transition temperature is lower than those of high-quality NbTiN films. Interestingly, even though the zero-temperature Ginzburg-Landau coherence length (=9.77 nm) is significantly shorter than the film thickness (=86 nm), we are still able to observe the Berezinskii-Kosterlitz-Thouless-like transition, indicating the two-dimensional (2D) signature of our three-dimensional (3D) sample. We propose that the mechanism of hidden 2D superconducting property is similar to the recently reported results of the disordered induced 3D to 2D superconductor transition. We suggest further theoretical work is required for studying our new experimental results.

中文翻译：

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超高真空磁控溅射在 Si 上生长的 NbTiN 薄膜中无序诱导的二维超导性

我们报告了在超高真空溅射制备的 Si 衬底上的铌钛氮化物 (NbTiN) 薄膜的生长和表征。我们表明超导转变温度低于高质量 NbTiN 薄膜的超导转变温度。有趣的是，即使零温度 Ginzburg-Landau 相干长度 (=9.77 nm) 明显短于薄膜厚度 (=86 nm)，我们仍然能够观察到类似 Berezinskii-Kosterlitz-Thouless 的跃迁，表明这两个- 我们的三维 (3D) 样本的维 (2D) 签名。我们提出隐藏的 2D 超导特性的机制类似于最近报道的无序诱导 3D 到 2D 超导体转变的结果。我们建议需要进一步的理论工作来研究我们的新实验结果。