TY  - JOUR
AU  - Yong, Z.
AU  - Trevisanutto, P. E.
AU  - Chiodo, L.
AU  - Santoso, I.
AU  - Barman, A. R.
AU  - Asmara, T. C.
AU  - Dhar, S.
AU  - Kotlov, A.
AU  - Terentjevs, A.
AU  - Della Sala, F.
AU  - Olevano, V.
AU  - Rübhausen, M.
AU  - Venkatesan, T.
AU  - Rusydi, A.
TI  - Emerging giant resonant exciton induced by Ta substitution in anatase TiO<sub>2</sub> : A tunable correlation effect
JO  - Physical review / B
VL  - 93
IS  - 20
SN  - 2469-9950
CY  - College Park, Md.
PB  - APS
M1  - PUBDB-2016-02073
SP  - 205118
PY  - 2016
AB  - Titanium dioxide (TiO<sub>2</sub>) has rich physical properties with potential implications for both fundamental physics and new applications. To date, the main focus of applied research is to tune its optical properties, which is usually done via doping and/or nanoengineering. However, understanding the role of d electrons in materials and possible functionalization of d-electron properties are still major challenges. Herewith, within a combination of an innovative experimental technique, high-energy optical conductivity, and state-of-the-art ab initio electronic structure calculations, we report an emerging, novel resonant exciton in the deep ultraviolet region of the optical response. The resonant exciton evolves upon low-concentration Ta substitution in anatase TiO<sub>2</sub> films. It is surprisingly robust and related to strong electron-electron and electron-hole interactions. The d- and f-orbital localization, due to Ta substitution, plays an unexpected role, activating strong electronic correlations and dominating the optical response under photoexcitation. Our results shed light on a new optical phenomenon in anatase TiO2 films and on the possibility of tuning electronic properties by Ta substitution.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000375997500003
DO  - DOI:10.1103/PhysRevB.93.205118
UR  - https://bib-pubdb1.desy.de/record/299960
ER  -