Pressure-induced successive phase transitions and Fano resonance engineering in lead-free piezoceramics KNbO3

We carried out detailed high-pressure Raman scattering studies on lead-free perovskite piezoceramics KNbO3 (KNO) with a smaller pressure interval so that the successive phase transition pressures are precisely determined (PO→T: 8.2 GPa; PT→C: 10.9 GPa). The pressure-quenched does not return to ambient orthorhombic completely. In this work, pressure-induced sequence is discussed in detail. Also, based pressure-dependent spectra of KNO, we have discovered clear evidence Fano resonance. It reveals role played by Raman-active continuum and discrete energy states condensed matter system under high enables resonances engineering arbitrary geometries [q∈(−∞, 0)]. These findings highlight opportunity for designing tuning wave transmission optical switch properties KNO via pressure.