Open AccessPressure induced band-gap changes in (Ba0.5Sr0.5)TiO3 (BST) from first-principles calculations
Author(s) -
Daoguo Yang,
Ru-Zhi Wang,
Li-Chun Xu,
Hui Fang,
Hui Yan
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.117309
Subject(s) - materials science , band gap , condensed matter physics , delocalized electron , semimetal , density of states , density functional theory , conduction band , electronic band structure , direct and indirect band gaps , computational chemistry , chemistry , optoelectronics , electron , physics , organic chemistry , quantum mechanics
The high-pressure behaviors of crystalline (Ba0.5Sr0.5)TiO3 (BST) are investigated, using the first-principles calculations based on the density functional theory. The results show that as pressure increases, the band gap of BST first increases and peaks at around 55 GPa, and then gradually decreases. The analysis of density of states shows that in the low-pressure region (0P55 GPa), the increase in band gap is due to the formation of anti-bonding states and bonding states in the conduction band and valence band, respectively. In the high-pressure region (P55 GPa), the delocalization phenomenon in dominant due to the fact that the delocaligation action exceeds the force of bonding state and anti-bonding state, which results in the decrease of the band gap.