UPS spectra and ferroelectric polaron model. UPS spectra near the Fermi level of SrTiO3 are shown with conceptual diagrams for the trapping mechanism of the photoinduced carriers and for the ferroelectric lattice distortion. The UPS spectra were taken at 20 K with and without the ultraviolet illumination. The laser power is ranging from 0.5 to 2.0 mJ/pulse, and the repetition rate is 30 Hz. The inset shows the UPS spectral weight at the Fermi level as a function of the illumination power.
Mizokawa Nanoscale Research Letters 2012 7:582 doi:10.1186/1556-276X-7-582