Structural phase transitions between layered Indium Selenide for inte-grated photonic memory

TL;DR

This paper demonstrates fast, reversible, and nonvolatile phase transitions between layered indium selenide structures using optical pulses, enabling potential applications in integrated photonic memory with low energy consumption.

Contribution

It introduces a novel method for rapid, reversible phase switching in layered In2Se3, leveraging atomistic transition pathways and broadband optical properties for photonic memory applications.

Findings

Reversible switching between alpha and beta In2Se3 structures achieved with nanosecond pulses.

Detailed atomistic transition pathways identified via high-resolution pair distribution function.

Broadband refractive index contrast and optical transparency characterized in thin films.

Abstract

The primary mechanism of optical memristive devices relies on the phase transitions between amorphous-crystalline states. The slow or energy hungry amorphous-crystalline transitions in optical phase-change materials are detrimental to the devices scalability and performance. Leveraging the integrated photonic platform, we demonstrate a single nanosecond pulse triggered nonvolatile and reversible switching between two layered structures of indium selenide (In2Se3). High resolution pair distribution function reveals the detailed atomistic transition pathways between the layered structures. With inter-layer shear glide and isosymmetric phase transition, the switching between alpha and beta structural states contain 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 initials calculations. The nonlinear resonator transmission spectra measure an incremental linear loss rate of 3.3 GHz introduced by 1.5 micrometer long In2Se3 covered lay-er, resulting from the combinations of material absorption and scattering.