Simulating Terahertz Field-Induced Ferroelectricity in Quantum Paraelectric SrTiO_{3}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Optics

Background:

• Strontium titanate (SrTiO3) exhibits a quantum paraelectric phase at low temperatures.
• Recent experiments show light can induce a ferroelectric phase transition in SrTiO3.

Purpose of the Study:

• To investigate the terahertz field-induced ferroelectric phase transition in SrTiO3.
• To elucidate the microscopic mechanisms behind light-induced ferroelectricity in SrTiO3.

Main Methods:

• Solving the time-dependent lattice Schrödinger equation.
• Utilizing first-principles calculations.
• Analyzing non-oscillatory second harmonic generation signals.

Main Results:

• Ferroelectricity arises from light-induced mixing of ground and excited lattice states.
• Non-oscillatory second harmonic generation confirms ferroelectricity, aligning with experimental data.
• The study reveals the microscopic details of this light-induced phase transition.

Conclusions:

• The observed ferroelectric phase transition in SrTiO3 is driven by quantum effects.
• Light-induced ferroelectricity in SrTiO3 is a unique phenomenon specific to its quantum paraelectric phase.
• Second harmonic generation serves as a key experimental signature for this transition.