The conduction band in inverse spinel structure of SnZn
2
O
4
is considerably almost the same (about 10.92
eV) the normal spinel structure. There is composed of the Sn-
sp
states, which are hybridized with the Zn-
sp
and O-
p
states. The valence band is somewhat narrower in inverse spinel (about 9.3 eV in comparison with 9.7 eV in normal
spinel). It is found that the upper valence bands (between -9.3 and 0 eV), is a mixture of Sn-
sp
, Zn-
d
and O-
p
states.
The lower valence bands situated in the range -20.4 to -16.1 eV is show to be of predominantly O-
s
states with minor
contribution of Sn-
sp
and Zn-
s
,
p
,
d
states.
DOS DOS
( a ) ( b )
Fig. 3
Partial and total density of states for (a) normal spinel and (b) inverse spinel structure of SnZn
2
O
4
.
CONCLUSIONS
The first-principle density functional calculations of structural and electronic properties of normal and
inverse spinel structures of SnZn
2
O
4
have been performed using the local density approximation (LDA). The results
indicated that the inverse spinel of SnZn
2
O
4
structure is more stable than normal one. The electronic band structure is
characterized as direct band gap for both structures. The conduction band is considerably wider in inverse spinel
-30 -20 -10 0 10 20
Energy (eV)
-30 -20 -10 0 10 20
Energy (eV)
s
p
p
Sn PDOS
S P
d
S P
d
Zn PDOS
Zn PDOS
Sn PDOS
O PDOS
O PDOS
Total DOS
Total DOS
s
p
s
p
s
p
p
