Structural Phase Transitions between Layered Indium Selenide for Integrated Photonic Memory

Abstract
The primary mechanism of optical memoristive devices relies on phase transitions between amorphous and crystalline states. The slow or energy-hungry amorphous–crystalline transitions in optical phase-change materials are detrimental to the scalability and performance of devices. Leveraging an integrated photonic platform, nonvolatile and reversible switching between two layered structures of indium selenide (In2Se3) triggered by a single nanosecond pulse is demonstrated. The high-resolution pair distribution function reveals the detailed atomistic transition pathways between the layered structures. With interlayer “shear glide” and isosymmetric phase transition, switching between the α- and β-structural states contains low re-configurational entropy, allowing reversible switching between layered structures. Broadband refractive index contrast, optical transparency, and volumetric effect in the crystalline–crystalline phase transition are experimentally characterized in molecular-beam-epitaxy-grown thin films and compared to ab initio calculations. The nonlinear resonator transmission spectra measure of incremental linear loss rate of 3.3 GHz, introduced by a 1.5 µm-long In2Se3-covered layer, resulted from the combinations of material absorption and scattering.
Description
This is the peer reviewed version of the following article: Li, T., Wang, Y., Li, W., Mao, D., Benmore, C. J., Evangelista, I., Xing, H., Li, Q., Wang, F., Sivaraman, G., Janotti, A., Law, S., Gu, T., Structural Phase Transitions between Layered Indium Selenide for Integrated Photonic Memory. Adv. Mater. 2022, 34, 2108261. https://doi.org/10.1002/adma.202108261, which has been published in final form at https://doi.org/10.1002/adma.202108261. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. © 2022 Wiley-VCH GmbH. This research was featured in UDaily on 04/15/2024, available at: https://www.udel.edu/udaily/2024/april/tingyi-gu-national-science-foundation-career-optical-memory/
Keywords
all-optical switching, In 2Se 3, optical memory, optical switching, structural phase transitions
Citation
Li, T., Wang, Y., Li, W., Mao, D., Benmore, C. J., Evangelista, I., Xing, H., Li, Q., Wang, F., Sivaraman, G., Janotti, A., Law, S., Gu, T., Structural Phase Transitions between Layered Indium Selenide for Integrated Photonic Memory. Adv. Mater. 2022, 34, 2108261. https://doi.org/10.1002/adma.202108261