TY - JOUR
T1 - Density Functional Theory Study of Electronic Structures in Lithium Silicates: $Li_2SiO_3$ and $Li_4SiO_4$
JO - Journal of Atomic and Molecular Sciences
VL - 3
SP - 185
EP - 200
PY - 2010
DA - 2010/01
SN - 1
DO - http://doi.org/10.4208/jams.110609.113009a
UR - https://global-sci.org/intro/article_detail/jams/8080.html
KW - electronic structure, density functional theory, lithium silicates, fusion.
AB - <p style="text-align: justify;">Lithium silicates, such as $Li_2SiO_3$ and $Li_4SiO_4$, are considered
as favorable candidates for the tritium breeding
materials of a nuclear fusion 
reactor. Their bulk electronic
properties and mechanics are important for the 
tritium behavior and
tritium breeding blanket designs. We have studied the 
structural and electronic properties of $Li_2SiO_3$ and $Li_4SiO_4$ bulks 
using density functional
theory (DFT) within generalized gradient approximation
(GGA). The
calculated crystal parameters are well consistent with the
 experimental 
results. The electronic band energy calculations show
that $Li_2SiO_3$ and $Li_4SiO_4$ are insulators with a band gap
of about 5.36 and 5.53 eV, respectively. 
Their valence band
properties are mainly determined by the oxygen 2$p$ orbital 
electrons.
The two types of oxygen atoms, nonbridging oxygen (NBO) atoms and
bridging 
oxygen (BO) atoms, in $Li_2SiO_3$ reveal significantly
different electron 
distribution of oxygen 2$p$ orbital. The Si 3$s$ and
3$p$ hybridization is observed 
in $Li_2SiO_3$, but not in $Li_4SiO_4$. In both lithium silicates, the electronic 
density
increases more steeply around $Li$ and $Si$ atom sites compared with
that around $O$ atoms. Additionally, the mechanical properties of both lithium silicates were 
calculated and discussed first time.</p>