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We present evidence of a drastic renormalization of the optical conductivity of graphene on SrTiO 3 resulting in almost full transparency in the ultraviolet region. These findings are attributed to resonant excitonic effects further supported by ab initio Bethe-Salpeter equation and density functional theory calculations. The (π, π*) orbitals of graphene and Ti-3 d t 2 g orbitals of SrTiO 3 are strongly hybridized and the interactions of electron-hole states residing in those orbitals play dominant role in the graphene optical conductivity. These interactions are present much below the optical band gap of bulk SrTiO 3. These results open a possibility of manipulating interaction strengths in graphene via d orbitals, which could be crucial for optical applications.
Publication date: 
1 Jan 2015

Pranjal Kumar Gogoi, Paolo E. Trevisanutto, Ming Yang, Iman Santoso, Teguh Citra Asmara, Aleksandrs Terentjevs, Fabio Della Sala, Mark B. H. Breese, T. Venkatesan, Yuan Ping Feng, Kian Ping Loh, Antonio H. Castro Neto, Andrivo Rusydi

Biblio References: 
Volume: 91 Pages: 035424
Physical Review B