Abstract
Fabricating complex transition metal oxides with a tunable bandgap without compromising their intriguing physical properties is a longstanding challenge. Here we examine the layered ferroelectric bismuth titanate and demonstrate that, by site-specific substitution with the Mott insulator lanthanum cobaltite, its bandgap can be narrowed by as much as 1 eV, while remaining strongly ferroelectric. We find that when a specific site in the host material is preferentially substituted, a split-off state responsible for the bandgap reduction is created just below the conduction band of bismuth titanate. This provides a route for controlling the bandgap in complex oxides for use in emerging oxide optoelectronic and energy applications.
| Original language | English |
|---|---|
| Article number | 689 |
| Journal | Nature Communications |
| Volume | 3 |
| DOIs | |
| State | Published - 2012 |
Funding
We thank J.F. Scott and S.S.A. Seo for discussions. This work was supported by the US. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division (synthesis, theory and electrical characterization) and the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (STEM–EELS and optical characterization). The optical measurement was in part conducted at the Center for Nanophase Materials Sciences, a DOE-BES user facility.