期刊
PHYSICAL REVIEW B
卷 94, 期 18, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevB.94.180104
关键词
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资金
- Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division
- Army Research Office [W911NF-14-1-0104]
- Department of Energy [DE-SC0012375]
- U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-06CH11357]
- U.S. Department of Energy, Office of Basic Energy Sciences [DE-FG02-07ER15920, DE-AC02-76SF00515]
- Carnegie Institution for Science
- National Science Foundation [CMMI-1334241, CHE-1111557]
- Office of Naval Research [N00014-12-1-1033, N00014-13-1-0509]
The dynamical processes associated with electric field manipulation of the polarization in a ferroelectric remain largely unknown but fundamentally determine the speed and functionality of ferroelectric materials and devices. Here we apply subpicosecond duration, single-cycle terahertz pulses as an ultrafast electric field bias to prototypical BaTiO3 ferroelectric thin films with the atomic-scale response probed by femtosecond x-ray-scattering techniques. We show that electric fields applied perpendicular to the ferroelectric polarization drive large-amplitude displacements of the titanium atoms along the ferroelectric polarization axis, comparable to that of the built-in displacements associated with the intrinsic polarization and incoherent across unit cells. This effect is associated with a dynamic rotation of the ferroelectric polarization switching on and then off on picosecond time scales. These transient polarization modulations are followed by long-lived vibrational heating effects driven by resonant excitation of the ferroelectric soft mode, as reflected in changes in the c-axis tetragonality. The ultrafast structural characterization described here enables a direct comparison with first-principles-based molecular-dynamics simulations, with good agreement obtained.
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