具AlB2晶格結構型態的過渡金屬二硼化合物有高熔點、高硬度、良導熱性、高化學穏定性、低電阻和低密度性質。這些特性具有相當高的應用價值。自從同樣結構的MgB2被發現超導臨界溫度約39K，有相當多的研究重新重視同樣結構的過渡金屬二硼化合物的物理性質。
　　本研究是以核磁共振（NMR）的技術探討過渡金屬二硼化合物TMB2 （TM= Ti、 Zr、 Hf、 V、 Nb和 Ta）的電子結構。在所有的研究樣品，量測到的硼原子核的NMR鬆弛時間，主要是來自B-2p電子的貢獻。從NMR自旋-晶格鬆弛時間推導所得的B-2p電子的費米能階態密度與理論計算有很好的吻合。此外，在TiB2、ZrB2 和 HfB2中，來自B-2p電子貢獻的費米能階態密度均小於同樣來自B-2p電子貢獻的VB2、NbB2 和 TaB2。本實驗量測結果符合理論計算所推論的化學穩定趨勢。

　　The AlB2-type transition metal diborides have the properties of high melting point, high hardness, high thermal conductivity, high chemical stability, low electrical resistivity, and low mass density. Those properties are useful for technological applications. Since the isostructural MgB2 was found to have the phenomenon of superconductivity at Tc ~ 39 K, there are a lot of research focusing on the physical character of the isostructural transition metal diborides.

　　In this investigation, we study the electronic structure of transition metal diborides, TMB2 (TM= Ti, Zr, Hf, V, Nb, and Ta) by nuclear magnetic resonance (NMR) techniques. For all studied samples, the p-orbital relaxation is the dominant mechanism for the observed relaxation at B nuclei. The deduced B-2p Fermi-level density of states (DOS) are in good agreement with theoretical values. In addition, partial B-2p Fermi-level DOS in TiB2, ZrB2, and HfB2 are consistent smaller than in VB2, NbB2, and TaB2. This observation is associated with the trend of chemical stability raised by theoretical calculations.

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