论文标题
基于NMR的间隙行为与量子大小效应有关
NMR-based gap behavior related to the quantum size effect
论文作者
论文摘要
我们对覆盖有聚乙烯基吡咯烷酮涂层的各种直径的PT纳米颗粒进行了$^{195} $ pt-核磁共振测量，以便检测量子大小效应和状态的电子密度的离散能级，这两种状态都在50多年前被库博预测。我们成功地分离了由表面和内部区域产生的信号，发现两个区域的核自旋晶格弛豫率都表明在高温下的金属行为。令人惊讶的是，两个区域的磁波动均在相同温度$ t^*$以下表现出异常行为，这表明了尺寸清晰的依赖性，并以$δ_\ mathrm {kubo} $进行了很好的缩放。这些结果表明，由于久保效应，PT纳米颗粒发生了大小可调的金属绝缘体过渡。
We conducted$^{195}$Pt-nuclear magnetic resonance measurements on various-diameter Pt nanoparticles coated with polyvinylpyrrolidone in order to detect the quantum size effect and the discrete energy levels in the electron density of states, both of which were predicted by Kubo more than 50 years ago. We succeeded in separating the signals arising from the surface and interior regions and found that the nuclear spin-lattice relaxation rates in both regions show the metallic behavior at high temperatures. Surprisingly, the magnetic fluctuations in both regions exhibited anomalous behavior below the same temperature $T^*$, which points to a clear size dependence and is well scaled with $δ_\mathrm{Kubo}$. These results suggest that a size-tunable metal-insulator transition occurs in the Pt nanoparticles as a result of the Kubo effect.
