1202.4786 (Woo Seok Choi et al.)

Band gap tuning in ferroelectric Bi4Ti3O12 by alloying LaTMO3 (TM = Ti,
V, Cr, Mn, Co, Ni, and Al)    [PDF]

Woo Seok Choi, Ho Nyung Lee

We fabricated ferroelectric Bi4Ti3O12 (BiT) single crystalline thin films
site-specifically substituted with LaTMO3 (TM = Al, Ti, V, Cr, Mn, Co, and Ni)
on SrTiO3 substrates by pulsed laser epitaxy. When transition metals are
incorporated into a certain site of the BiT, some of BiT-LaTMO3 showed a
substantially decreased band gap, coming from the additional optical transition
between oxygen 2p and TM 3d states. Specifically, all alloys with Mott
insulators revealed a possibility of band gap reduction. Among them, BiT-LaCoO3
showed the largest band gap reduction by ~1 eV, positioning itself as a
promising material for highly efficient opto-electronic devices.

View original: http://arxiv.org/abs/1202.4786