Midinfrared-light-induced ferroelectricity in oxide paraelectrics via nonlinear phononics

Article

关键词: FUNCTIONAL PERTURBATION-THEORY;    AUGMENTED-WAVE METHOD;    INDUCED SUPERCONDUCTIVITY;    RAMAN-SCATTERING;    SOFT-MODE;    TRANSITION;    PHASE;    SPECTROSCOPY;    YBA2CU3O6.5;    EXCITATION;   

DOI  :  10.1103/PhysRevB.95.134113

来源: SCIE

【 摘 要 】

I show that a nonequilibrium paraelectric to ferroelectric transition can be transiently induced usingmidinfrared pulses. This relies on a quartic lQ(lz)(2) Q(hx)(2) coupling between the lowest (Q(lz)) and highest ( Q(hx)) frequency infrared-active phonon modes of a paraelectric material. Density functional calculations show that the coupling constant l is negative, which causes a softening of the Q(lz) mode when the Q(hx) mode is externally pumped. A rectification along the Q(lz) coordinate that stabilizes the nonequilibrium ferroelectric state occurs only above a critical threshold for the electric field of the pump pulse, demonstrating that this is a nonperturbative phenomenon. A first-principles calculation of the coupling between light and the Q(hx) mode shows that ferroelectricity can be induced in the representative case of strained KTaO3 by a midinfrared pulse with a peak electric field of 17 MVcm(-1) and duration of 2 ps. Furthermore, other odd-order nonlinear couplings make it possible to arbitrarily switch off the light-induced ferroelectric state, making this technique feasible for all-optic devices.

【 授权许可】

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