The Classical-to-Quantum Crossover in strain-induced ferroelectric transition in SrTiO$_3$ membranes

Jiarui Li; Yonghun Lee; Yongseong Choi; Jong-Woo Kim; Paul Thompson; Kevin J. Crust; Ruijuan Xu; Harold Y. Hwang; Philip J. Ryan; Wei-Sheng Lee

arXiv · 2502.02586

The Classical-to-Quantum Crossover in strain-induced ferroelectric transition in SrTiO$_3$ membranes

Jiarui Li·Yonghun Lee·Yongseong Choi·Jong-Woo Kim·Paul Thompson·Kevin J. Crust·Ruijuan Xu·Harold Y. Hwang·Philip J. Ryan·Wei-Sheng Lee

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Abstract

Mechanical strain presents an effective control over symmetry-breaking phase transitions. In quantum paralelectric SrTiO3, strain can induce the ferroelectric transition via modification of local Ti potential landscape. However, brittle bulk materials can only withstand limited strain range (~0.1%). Taking advantage of nanoscopically-thin freestanding membranes, we demonstrated in-situ strain-induced reversible ferroelectric transition in a single freestanding SrTiO3 membranes. We measure the ferroelectric order by detecting the local anisotropy of the Ti 3d orbital using X-ray linear dichroism at the Ti-K pre-edge, while the strain is determined by X-ray diffraction. With reduced thickness, the SrTiO3 membranes remain elastic with >1% tensile strain cycles. A robust displacive ferroelectricity appears beyond a temperature-dependent critical strain. Interestingly, we discover a crossover from a classical ferroelectric transition to a quantum regime at low temperatures, which enhances strain-induced ferroelectricity. Our results offer a new opportunities to strain engineer functional properties in low dimensional quantum materials and provide new insights into the role of the ferroelectric fluctuations in quantum paraelectric SrTiO3.

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Jiarui Li, Yonghun Lee, Yongseong Choi, Jong-Woo Kim, Paul Thompson, Kevin J. Crust, Ruijuan Xu, Harold Y. Hwang, Philip J. Ryan, Wei-Sheng Lee. 2025-02-04. The Classical-to-Quantum Crossover in strain-induced ferroelectric transition in SrTiO$_3$ membranes. https://arxiv.org/abs/2502.02586

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