低維度金屬鏈狀排列結構的化合物具有超導性質與CDW (charge-density-wave) 轉換共存的現象等物理特性，而這些特性中，在最近這幾年引起注意的是由電子－聲子交互作用耦合所產生超導特性。
屬於準一維Nb結構系統的Nb3Ch4(Ch = S, Se, and Te)，其超導特性在先前已被研究過了。然而，以Nb原子為基元的準二維結構化合物至今仍未有進一步的相關研究，因此，準二維Nb結構化合物的研究對於了解低維度系統的超導特性是有其必要性的。對此計劃而言，由準二維Nb 網狀系統所組成的Nb4MSi (M = Ni, Co, and Fe)，是相當適合的研究對象。
在本篇論文裡，將利用核磁共振(NMR)的技術來量測並探討同是屬於CuAl2 結構的Nb4FeSi、Nb4CoSi和Nb4NiSi 的電子特性。藉由量測93Nb的NMR 頻譜來討論各個樣品的四重極效應、奈特位移及自旋－晶格鬆弛時間。

Compounds with a low-dimensional metallic chain exhibit to several physical properties, including superconductivity and charge density wave(CDW) formation. Among these properties, the superconductivity under a weak coupling regime of electron–phonon interactions has attracted attention in the last several years. The superconductivity of these compounds has previously been reported for Nb3Ch4 (Ch = S, Se, and Te) with a quasi-1D Nb topology. However, Nb-based compounds with a quasi-2D have not been studied. Thus, the research on a quasi-2D Nb network is necessary to understand the superconductivity in this low-dimensional system. Nb4MSi (M = Ni, Co, and Fe) is a suitable model for this purpose because its crystal configuration is composed of a quasi-2D Nb network.
In this thesis﹐we have performed a systematic study of the CuAl2-type compounds Nb4FeSi、Nb4CoSi, and Nb4NiSi using 93Nb NMR spectroscopy. The quadrupole splitting, the Knight shift(K), as well as the spin-lattice relaxation time(T1) of each individual compound have been identified.

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