Fig. 1. (a) Typical I-V characteristics of the LTO/STO at room temperature. The insets show the schematic measurement setup. (b) XRD pattern of LTO/STO sample.

Fig. 2. (a) Typical waveforms recorded by oscilloscope with 1 MΩ input impedance without any bias when laser spot irradiated the region from position 1.5 mm to position −1.5  mm. (b) Steady waveforms’ peak voltages depended linearly on the spot positions.

Fig. 3. (a) Typical waveforms with different on-sample laser power from 7.8 to 131 mW at position of 1.5 mm. (b) LPV dependence on the on-sample laser power.

Fig. 4. (a) Typical waveforms with bias currents applied from 0 to 350 μA at the position of 1.5 mm. (b) Laser-induced photovoltage dependence on the bias current.

Fig. 5. (a) Laser-induced photovoltages under different pressures with a 1 mA bias current. (b) Laser-induced photovoltages under different pressures with a 3 mA bias current.