Design of a low band gap oxide ferroelectric: Bi6Ti4O17
Physics Department, National University of Singapore - 2 Science Drive 3, Singapore 117542, Singapore
2 College of Physics and Communication Electronics, Jiangxi Normal University - Nanchang, Jiangxi 33022, PRC
3 Materials Science and Technology Division, Oak Ridge National Laboratory - Oak Ridge, TN 37831-6114, USA
Accepted: 1 April 2011
A strategy for obtaining low band gap oxide ferroelectrics based on charge imbalance is described and illustrated by first-principles studies of the hypothetical compound Bi6Ti4O17, which is an alternate stacking of the ferroelectric Bi4Ti3O12. We find that this compound is ferroelectric, similar to Bi4Ti3O12 although with a reduced polarization. Importantly, calculations of the electronic structure with the recently developed functional of Tran and Blaha yield a much reduced band gap of 1.83 eV for this material compared to Bi4Ti3O12. Therefore, Bi6Ti4O17 is predicted to be a low band gap ferroelectric material.
PACS: 78.20.Ci – Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity) / 77.55.fp – Other ferroelectric films / 71.20.Ps – Other inorganic compounds
© EPLA, 2011