Local strain inhomogeneities during electrical triggering of a metal-insulator transition revealed by X- ray microscopy

• 成果类型: Article
• 署名作者: Salev, Pavel; Kisiel, Elliot; Sasaki, Dayne; Gunn, Brandon; He, Wei; Feng, Mingzhen; Li, Junjie; Tamura, Nobumichi; Poudyal, Ishwor; Islam, Zahirul; Takamura, Yayoi; Frano, Alex; Schuller, Ivan K.
• 署名单位: University of Denver; University of California System; University of California San Diego; United States Department of Energy (DOE); Argonne National Laboratory; University of California System; University of California Davis; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13675
• DOI: 10.1073/pnas.2317944121
• 发表日期: 2024-08-20
• 关键词: magnetic-anisotropy; rnio3 perovskites; phase-separation

摘要

Electrical triggering of a metal-insulator transition (MIT) often results in the formation of characteristic spatial patterns such as a metallic filament percolating through an insulating matrix or an insulating barrier splitting a conducting matrix. When MIT triggering is driven by electrothermal effects, the temperature of the filament or barrier can be substantially higher than the rest of the material. Using X- ray microdiffraction and dark- field X- ray microscopy, we show that electrothermal MIT triggering leads to the development of an inhomogeneous strain profile across the switching device, even when the material does not undergo a pronounced, discontinuous structural transition coinciding with the MIT. Diffraction measurements further reveal evidence of unique features associated with MIT triggering including lattice distortions, tilting, and twinning, which indicate structural nonuniformity of both low- and high- resistance regions inside the switching device. Such lattice deformations do not occur under equilibrium, zero- voltage conditions, highlighting the qualitative difference between states achieved through increasing temperature and applying voltage in nonlinear electrothermal materials. Electrically induced strain, lattice distortions, and twinning could have important contributions in the MIT triggering process and drive the material into nonequilibrium states, providing an unconventional pathway to explore the phase space in strongly correlated electronic systems.