MAGNETIC PROPERTIES OF ICOSAHEDRAL COPPER-COATED COBALT CLUSTERS

2004 ◽  
Vol 11 (01) ◽  
pp. 15-20 ◽  
Author(s):  
BAOLIN WANG ◽  
XIAOSHUANG CHEN ◽  
GUIBIN CHEN ◽  
GUANGHOU WANG ◽  
JIJUN ZHAO

The structural and magnetic properties of Cu -coated Co clusters are investigated with empirical genetic algorithm simulation and a spin-polarized spd tight-binding model Hamiltonian. In some specific stoichiometric compositions, icosahedral Co n (n=1, 2, 4, 7, 13, 19, 55) clusters perfectly coated with A Cu monolayer or dual layer are obtained. The outer Cu layers lead to significant modification of the magnetic moment of the Co core, depending on the structure and thickness of the Cu layers. The interaction between Cu and Co atoms induces a nonzero magnetic moment for Cu atoms.

2006 ◽  
Vol 32 (1-2) ◽  
pp. 375-378 ◽  
Author(s):  
P. Sankowski ◽  
P. Kacman ◽  
J. Majewski ◽  
T. Dietl

1989 ◽  
Vol 03 (01) ◽  
pp. 135-161 ◽  
Author(s):  
FUMIKO YONEZAWA ◽  
KEIKO ISHIDA ◽  
FUMITOSHI SATO

We propose a two-band tight-binding model Hamiltonian to describe the behaviour of electrons in amorphous semiconductor superlattices. Our model Hamiltonian is characterized by its off-diagonal terms υz in direction z which is perpendicular to layers in a superlattice; we define υz as a parameter which represents the dimension of well layers accompanying the change in a well-layer width Lw under the condition that a barrier-layer width is fixed. On the basis of this model, we calculate the density of states D(E) and the absorption spectra I(E), from which we estimate the exponential-tail widths E0 and Eu of D(E) and I(E), respectively. We discuss the ways in which these widths E0 and Eu are influenced (i) by the dimension of the system, (ii) by the dispersion of well-layer widths and (iii) by the degree of disorder. We also propose the possibility to improve the photovoltaic efficiency in solar cells composed of amorphous semiconductor superlattices.


Sign in / Sign up

Export Citation Format

Share Document