Small Size Bimetallic And Trimetallic Alloy Clusters:a First-Principles Investigations

One of the major goals of cluster science has been dedicated to find out the stable clusters with unique electronic, optical, acoustical, magnetic, and chemical properties in the field of cluster research. In this work, we extend our investigations on clusters from the following two aspects. Firstly, we performed a density function theory calculation on the vanadium-doped lithium clusters VLin (n=1-13) to search for the superatoms cluster. It is found that the doping with V atom can significantly enhances the structure stability of the clusters. A single Li-atom-capped structure of the VLin-1 cluster is a dominant growth pattern, while a high symmetry cage-like structure occures when n is lager than 8 with the impurity V atom locates in the center of the cage. As the number of Li atoms increasing, the magnetic moment of VLin clusters varies from 0 to 6μB, which shows potential applications in spin-controllable energy storage electronics. Molecular orbitals analysis shows the VLin clusters with cage-like structures are identified as superatoms. For an example, VLi8 has an electronic configuration of 1S21P61D5 with the magnetic moment of 5μB, exhibiting Hund’s filling rule of maximizing the spin like atoms. Thus VLi8 can analogue a signle Mn2+ ion. Moreover, we found that magnetic superatoms exist in VLin clusters with an endohedral V atom from the size of n=8 to 13. Electronic shell model and jellium sphere model can successfully explain the stability and electronic properties of these superatoms clusters. This work provides a theoretical basis for searching and constructing a bimetallic alloy superatoms clusters with special magnetic properties and high stability, exploring the microscopic mechanism of the novel physical and chemical properties of alloy superatoms clusters. Secondly, we systematically studied three types of transition-metal atoms doped trimetallic clusters and got considerable amounts of magnetic clusters. For the case of FeAlAun-i, a single Au atom edge-capped structure of the FeAlAun-1 cluster is a dominant growth pattern. The doping with Fe and Al atom can stabilize the gold clusters and enhance the chemical activity. The FeAlAun clusters show a pronounced odd-even oscillation with the increasing of Au atoms. For the case of AlMnAun(n= 1-7), these clusters tend to form 3D isomers with flat structures. The doping not only enhances the stabilities of the lowest-energy structures, but also introduces the high magnetic moment. Interestingly, chiral structures have been found in size 5,6 and 7 of AlMnAun clusters. In the case of GaMnLin (n=1-12) clusters, the lowest-energy structures of these clusters prefer to forming 3D cage structures, where the Mn atom likes to sit in the center and the Ga atom favors the edge position. It is found that doping of Mn and Ga atoms can enhance the stabilities of Lin clusters. These trimetallic clusters also prossess the magnetic moment varying from 0 to 5μB. The results show that these stable clusters with tailored magnetic porperties, electronic configurations, and chiral structures can be used as building blocks with potential applications in new nanomaterials.