Details

Autor(en) / Beteiligte

• Kong, Yueyue
• Zhang, Hong
• Cheng, Xinlu

Titel

Modulation of Oxygen Vacancy on Midinfrared Light‐Induced Ferroelectricity of KTaO3

Ist Teil von

• physica status solidi (b), 2021-10, Vol.258 (10), p.n/a

Erscheinungsjahr

2021

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Nonlinear phononics plays an important role in intense laser–solid interactions, especially in light‐induced superconductivity, polarized and ferroelectric phases. Herein, by nonlinear coupling of phonon modes, the modulation of oxygen vacancy defects on the dynamic properties of midinfrared light‐induced ferroelectricity of cubic KTaO3 is studied. It is found that oxygen vacancy causes the coupling constant l between the high‐frequency phonon mode and the low‐frequency phonon mode to be negative, which means that the lowest frequency infrared‐active phonon mode (Qlz) is softened when highest‐frequency infrared‐active phonon mode (Qhx) is exteriorly pumped; it is proved that the Qlz mode can be softened when the KTaO3 contains 1/8, 1/4, and 2/3 of oxygen vacancies. When the KTaO3 contains a quarter of oxygen vacancies, it can effectively enhance the coupling constant, reduce the damping effect, and induce the ferroelectricity of KTaO3. But the Qlz mode cannot be softened when there are 3/8 of oxygen vacancies in KTaO3. Overall, the findings strongly support that turning the photoinduced ferroelectricity of KTaO3 by oxygen vacancy defects is desirable, which provides an effective strategy for controlling the light‐induced ferroelectricity in the all‐optical devices. It is found that oxygen vacancy can cause Qlz mode softening; and KTaO3 containing 1/8, 1/4, and 2/3 of oxygen vacancies can achieve dynamic stability of their own lowest‐frequency infrared mode through the midinfrared excitation of the highest‐frequency infrared mode. Among them, KTaO3‐VO1/4 has the best promotion effect.