Energetically Favored One-Dimensional Moir\'e Superstructure in the Pseudo-Square Lattice GdTe3

TL;DR

This study demonstrates the formation of energetically favored one-dimensional moiré superstructures in GdTe3, a pseudo-tetragonal layered crystal, expanding moiré physics beyond traditional hexagonal systems and revealing new electronic modulations.

Contribution

It introduces a method to create and analyze 1D moiré superstructures in GdTe3, a low-symmetry layered crystal, using controlled stacking and TEM techniques.

Findings

Successful realization of 1D moiré superstructures in GdTe3.

Observation of electronic property modulations linked to the moiré pattern.

Expansion of moiré phenomena exploration to non-hexagonal layered crystals.

Abstract

Moir\'e engineering in layered crystals has recently gained considerable attention due to the discovery of various structural and physical phenomena, including interfacial reconstruction, superconductivity, magnetism, and distinctive optoelectronic properties. Nevertheless, most explored moir\'e systems have been limited to hexagonal lattices, thereby constraining a comprehensive understanding and technological application of moir\'e phenomena in general layered crystals. Here, we investigate GdTe3, a pseudo-tetragonal layered crystal, as a platform to explore unconventional moir\'e phenomena. GdTe3 exhibits a slight in-plane distortion correlated with the direction of charge density wave formation. Through vertical stacking of layers with different distortions-induced via a controlled strain/release process-we realize energetically favorable one-dimensional (1D) moir\'e superstructures. Using transmission electron microscopy (TEM), including high-resolution scanning TEM imaging, dark-field TEM imaging, and sample tilting experiments, we systematically examine stacking variations across the 1D moir\'e structure. Additionally, electron energy loss spectroscopy reveals modulations in electronic properties associated with the 1D moir\'e structure. Our findings expand the scope of moir\'e systems beyond conventional hexagonal twistronics, enabling exploration of moir\'e phenomena in low-symmetry van der Waals crystals.