2008/02/21 by Marisol Alcántara Ortigoza, Talat S. Rahman · 36 citations
Chemistry · Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Ab initio #Atom (system on chip) #Atomic physics #Band gap #Chemistry #Condensed matter physics #Copper-based nanomaterials and applications #Crystallography #Electronic structure #Materials science #Nanocluster Synthesis and Applications #Physics #Quantum mechanics #cond-mat.mtrl-sci #nanoparticles nucleation surface interactions
paper · pdf · doi:10.1103/physrevb.77.195404
published in Physical Review B 77(19) (American Physical Society) · 16 figures
arxiv created 2008/02/21 · openalex publication_date 2008/05/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Ab initio calculations of the structure and electronic density of states (DOS) of the perfect core-shell Ag27Cu7 nanoalloy attest to its D5h symmetry and confirm that it has only six nonequivalent (two Cu and four Ag) atoms. The analyses of bond length, average formation energy, and heat of formation of Ag27Cu7 and L12 bulk Ag-Cu alloys provide an explanation for the relative stability of the former with respect to the other nanoalloys in the same family. The highest occupied molecular orbital--lowest unoccupied molecular orbital gap is found to be 0.77\phantom\rule0.3em0exeV, which is in agreement with previous results. The analyses of the DOS of Ag27Cu7, L12 Ag-Cu alloys, and related systems provide insight into the effects of low coordination, contraction or expansion, and the presence of foreign atoms on the DOS of Cu and Ag. While some characteristics of the DOS are reminiscent of those of the phonon-stable L12 Ag-Cu alloys, the Cu and Ag states hybridize significantly in Ag27Cu7, compensating for the d-band narrowing that each atom undergoes and hindering the dip in the DOS found in the bulk alloys. Charge density plots of Ag27Cu7 provide further insight into the relative strengths of the various interatomic bonds. Our results for the electronic and geometric structures of this nanoalloy can be explained in terms of length and strength hierarchies of the bonds, which may have implications also for the stability of alloys in any phase or size.