In-Plane Chirality Control of a Charge Density Wave by Means of Shear Stress.

Qi, Weiyan; Ponzoni, Stefano; Huitric, Guénolé; Grasset, Romain; Laplace, Yannis; Cario, Laurent; Zobelli, Alberto; Marsi, Marino et al. · Adv Mater · 2024

basic_science · Level V

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Abstract

The transition metal dichalcogenide 1T-TaS<sub>2</sub> exhibits a Charge Density Wave (CDW) with in-plane chirality. Due to the rich phase diagram, the Ferro-Rotational Order (FRO) can be tuned by external stimuli. The FRO is studied by Angle-Resolved Photoelectron Spectroscopy (ARPES), Raman spectroscopy, and Selected Area Electron Diffraction (SAED). The in-plane chirality of the CDW is lost at the transition from Nearly-Commensurate (NC) to In-Commensurate (IC) phase and can be controlled by applying shear stress to the sample while cooling it through the transition from IC-CDW to NC-CDW. Based on these observations, a protocol is proposed to achieve reliable, non-volatile state switching of the FRO configuration in 1T-TaS<sub>2</sub> bulk crystals. These results pave the way for new functional devices in which in-plane chirality can be set on demand.