Bifurcation response in a KH2PO4crystal near the ferroelectric transition

Phase locking and period-doubling bifurcation are observed to characterize the nonlinear response of a driven K${\mathrm{H}}_2$P${\mathrm{O}}_4$ crystal at temperatures near the ferroelectric phase transition, where the crystal may well be represented by a coupled system of two anharmonic oscillators, a polarization-mode oscillator and an elastic shear-mode oscillator coupled by the piezoelectric effect.