First-principles Study Of The Geometric, Electronic And Magnetic Properties Of Germanium-based Ge_nM Clusters

In this thesis, we present the investigation about the geometry, the electronic andmagnetic properties of the B doped germanium GenB cluster and the cobalt doped ger-manium GenCo cluster using the density functional theory (DFT).The growth behavior and electronic properties of the B dopant GenB clusters havebeen investigated using the first-principles method. According to the results, the dopantB atom can enhance the stability of the pure clusters; the GenB clusters have big HOMO-LUMO Gaps. There are two different models capable of forming GenB clusters, whichare the cluster with B atom concaved in Gen, and the cluster obtained from one Ge atom ofthe Gen+1 substituted by one B atom. And the GenB clusters have two structure elementsthat are Ge9 cluster and the Ge10 cluster. The Ge17Co cluster is more stable than itsneighbor clusters.The growth behavior and magnetic properties of the GenCo clusters have been in-vestigated using the density functional theory with the Dmol3 software. The doping ofthe Co atom enhances the stability of the host Gen clusters. Unlike the transition-metaldoped Sin clusters, the quenching of magnetic moments has not been found in the GenCoclusters. It may have relation with the orbital and the charge of the Ge and Co atoms.