TY  - JOUR
A1  - Schifferle, Lukas
A1  - Speziale, Sergio
A1  - Lobanov, Sergey S.
T1  - High-pressure evolution of the refractive index of MgO up to 140 GPa
T2  - Journal of applied physics
N2  - Refractive index provides fundamental insights into the electronic structure of materials. At high pressure, however, the determination of refractive index and its wavelength dispersion is challenging, which limits our understanding of how physical properties of even simple materials, such as MgO, evolve with pressure. 
Here, we report on the measurement of room-temperature refractive index of MgO up to similar to 140 GPa. 
The refractive index of MgO at 600 nm decreases by similar to 2.4% from similar to 1.737 at 1 atm to similar to 1.696 (+/- 0.017) at similar to 140 GPa. 
Despite the index at 600 nm is essentially pressure independent, the absolute wavelength dispersion of the refractive index at 550-870 nm decreases by similar to 28% from similar to 0.015 at 1 atm to similar to 0.011 (+/- 8.04 x 10(-4)) at similar to 103 GPa. 
Single-effective-oscillator analysis of our refractive index data suggests that the bandgap of MgO increases by similar to 1.1 eV from 7.4 eV at 1 atm to similar to 8.5 (+/- 0.6) eV at similar to 103 GPa.
Y1  - 2022
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/65395
SN  - 0021-8979
SN  - 1089-7550
VL  - 132
IS  - 12
PB  - AIP Publishing
CY  - Melville
ER  -