Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255, USA.
J Phys Condens Matter. 2011 Mar 23;23(11):115501. doi: 10.1088/0953-8984/23/11/115501. Epub 2011 Mar 1.
We report very small (27)Al metallic shifts in a series of Cu-Zr-Al bulk metallic glasses. This observation and the Korringa type of spin-lattice relaxation behavior suggest that s-character wavefunctions weakly participate in bonding and opens the possibility of enhanced covalency (pd hybridization) with increasing Al concentration, in good agreement with elastic constants and hardness measurements. Moreover, ab initio calculations show that this bonding character originates from the strong Al 3p band and Zr 4d band hybridization since their atomic energy levels are closer to each other while the Al 3s band is localized far below the Fermi level. This study might provide a chemical view for understanding flow and fracture mechanisms of these bulk glass-forming alloys.
我们在一系列铜-锆-铝大块金属玻璃中发现了非常小的（27）Al 金属位移。这一观察结果和 Korringa 型自旋晶格弛豫行为表明，s 特征波函数在一定程度上参与了成键，并且随着 Al 浓度的增加，共价键（pd 杂化）的可能性增大，这与弹性常数和硬度测量结果一致。此外，从头算计算表明，这种成键特性源于 Al 3p 带和 Zr 4d 带的强烈杂化，因为它们的原子能级彼此更接近，而 Al 3s 带则远远低于费米能级而局域化。这项研究可能为理解这些大块非晶形成合金的流动和断裂机制提供了一种化学观点。
