Shin Dongbin, Latini Simone, Schäfer Christian, Sato Shunsuke A, Baldini Edoardo, De Giovannini Umberto, Hübener Hannes, Rubio Angel
Max Planck Institute for the Structure and Dynamics of Matter and Center for Free Electron Laser Science, 22761 Hamburg, Germany.
Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, 412 96 Göteborg, Sweden.
Phys Rev Lett. 2022 Oct 14;129(16):167401. doi: 10.1103/PhysRevLett.129.167401.
Recent experiments have demonstrated that light can induce a transition from the quantum paraelectric to the ferroelectric phase of SrTiO_{3}. Here, we investigate this terahertz field-induced ferroelectric phase transition by solving the time-dependent lattice Schrödinger equation based on first-principles calculations. We find that ferroelectricity originates from a light-induced mixing between ground and first excited lattice states in the quantum paraelectric phase. In agreement with the experimental findings, our study shows that the nonoscillatory second harmonic generation signal can be evidence of ferroelectricity in SrTiO_{3}. We reveal the microscopic details of this exotic phase transition and highlight that this phenomenon is a unique behavior of the quantum paraelectric phase.
最近的实验表明，光可以诱导SrTiO₃从量子顺电相转变为铁电相。在此，我们通过基于第一性原理计算求解含时晶格薛定谔方程，研究这种太赫兹场诱导的铁电相变。我们发现，铁电性源于量子顺电相中基态与第一激发晶格态之间的光致混合。与实验结果一致，我们的研究表明，非振荡二次谐波产生信号可以作为SrTiO₃中铁电性的证据。我们揭示了这种奇异相变的微观细节，并强调这一现象是量子顺电相的独特行为。
