Electromechanical Hysteresis in Phase Change Material Sb2S3

TL;DR

This study investigates electromechanical hysteresis in Sb2S3, revealing that observed signals are due to non-piezoelectric effects and differ between crystalline and amorphous phases, impacting its use in memory devices.

Contribution

The paper clarifies the origin of hysteresis in Sb2S3, demonstrating it is not due to piezoelectricity and highlighting differences between crystalline and amorphous phases.

Findings

Hysteretic behavior is absent in glassy Sb2S3.

Electromechanical signals are primarily from non-piezoelectric effects.

Crystalline and amorphous Sb2S3 show different electrical behaviors.

Abstract

Antimony sulfide is an emerging phase change material for optical and electrical memory and computation elements. It has additionally been reported as a ferroelectric, with recent evidence from hysteresis in piezoresponse force microscopy. Here, we complete a rigorous set of piezoresponse force microscopy experiments on a congruently crystallized Sb2S3 glass-ceramic, where piezoelectric coupling should be forbidden in glassy Sb2S3. We replicate previous results and reveal that the behavior is absent in glassy Sb2S3 but show that the response originates primarily from non-piezoelectric contributions to the signal caused by an applied voltage. This hysteretic behavior in piezoresponse force microscopy is quite similar to some electrochemically active non-ferroelectric oxides, but uniquely, it appears here with a very clear spatial contrast that is decoupled from surface topography. This shows that the electromechanical signal reflects bulk-like properties and reveals differences in electrical behavior of crystalline and amorphous phases of Sb2S3.