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从理论上提出了硅的一种新型金属性亚稳相,并通过弹性常数和声子谱的计算验证了该结构在常压下的稳定性.该结构可以通过以?-La Si5为前驱物,将其中的La原子去除获得.该结构中隧道型空隙的存在使其密度低于金刚石型结构的Si-I相.在这种结构中,有40%的硅原子为5配位,其他硅原子为4配位.电子结构的计算表明该结构具有金属导电性.导电性主要由于5配位原子的存在导致价电子出现离域性.配位数的改变也使得硅原子之间发生了一定的电荷转移,出现离子性.该结构的化学键中同时存在共价性、金属性和离子性.
A new metallic metastable phase of silicon was proposed theoretically and the stability of the structure at atmospheric pressure was verified by the calculation of the elastic constants and the phonon spectrum.The structure can be obtained by using-LaSi5 as precursor , In which the La atom is removed, and the presence of tunnel voids in this structure results in a lower density than the diamond-type Si-I phase, in which 40% of the silicon atoms are 5-coordinated and the other silicon Atomic coordination of 4. Electronic structure calculations show that the structure has metal conductivity. Conductive mainly due to the presence of 5-coordinated atoms valence electrons appear delocalization. Coordination changes also make a certain amount of silicon atoms Of the charge transfer, the emergence of ionic structure of the chemical bond coexistence, metallinity and ionicity.