"Hidden phases" are metastable collective states of matter that are typically not accessible on equilibrium phase diagrams. These phases can host exotic properties in otherwise conventional materials and hence may enable novel functionality and applications, but their discovery and access are still in early stages. Using intense terahertz electric field excitation, we show that an ultrafast phase transition into a hidden ferroelectric phase can be dynamically induced in the quantum paraelectric SrTiO3. The induced lowering in crystal symmetry yields dramatic changes in the phonon excitation spectra. Our results demonstrate collective coherent control over material structure, in which a single-cycle field drives ions along the microscopic pathway leading directly to their locations in a new crystalline phase on an ultrafast timescale.
@article{arxiv.1812.10785,
title = {Terahertz-Field-Induced Ferroelectricity in Quantum Paraelectric SrTiO$_3$},
author = {Xian Li and Tian Qiu and Jiahao Zhang and Edoardo Baldini and Jian Lu and Andrew M. Rappe and Keith A. Nelson},
journal= {arXiv preprint arXiv:1812.10785},
year = {2019}
}