Temperature evolution of the band-gap in BiFeO3 traced by resonant Raman scattering

Abstract

Knowledge of the electronic band structure of multiferroic oxides, crucial for the understanding and tuning of photo-induced effects, remains very limited even in the model and thoroughly studied BiFeO3. Here, we investigate the electronic band structure of BiFeO3 using Raman scattering with twelve different excitation wavelengths ranging from the blue to the near infrared. We show that resonant Raman signatures can be assigned to direct and indirect electronic transitions, as well as in-gap electronic levels, most likely associated to oxygen vacancies. Their temperature evolution establishes that the remarkable and intriguing variation of the optical band-gap can be related to the shrinking of an indirect electronic band-gap, while the energies for direct electronic transitions remains nearly temperature independent.

5 pages, 4 figures

References in corpus (6)

• The beta Phase of Multiferroic Bismuth Ferrite and its beta-gamma Metal-Insulator Transition
• Room temperature coexistence of large electric polarization and magnetic order in BiFeO3 single crystals
• Light-induced size changes in BiFeO3 crystals
• Linear and Nonlinear Optical constants of BiFeO_3
• Electric field effect on BiFeO${}_3$ single crystal investigated by Raman spectroscopy
• Use of resonance Raman spectroscopy to study the phase diagram of PbZr0.52Ti0.48O3

Cited by in corpus (6)

• Ab Initio Approach to Second-order Resonant Raman Scattering Including Exciton-Phonon Interaction
• Temperature-dependent photo-response in multiferroic BiFeO${}_3$ revealed by transmission measurements
• Simplified approach to the magnetic blue shift of Mott gaps
• Impact of the surface phase transition on magnon and phonon excitations in BiFeO3 nanoparticles
• Understanding electronic excited states in BiFeO${}_3$ via ab initio calculations and symmetry analysis
• Flipping of electronic spins in BiFeO${}_3$ via chiral $d-d$ excitations