One-Dimensional Ionic-Bonded Structures in NiSe Nanowire

TL;DR

This paper reports the discovery of ionic-bonded one-dimensional structures in NiSe nanowires, identified through advanced microscopy and theoretical calculations, revealing new phases with potential for novel electronic and magnetic properties.

Contribution

It introduces the first observation of ionic-bonded 1D structures in NiSe nanowires and characterizes their phases and bonding nature, expanding the understanding of 1D materials.

Findings

Identified four distinct structural phases of NiSe nanowires.

Revealed ionic bonds as the bonding mechanism, unlike typical van der Waals interactions.

Suggested potential for unique electronic and magnetic properties.

Abstract

One-dimensional van der Waals (1D vdW) materials, characterized by atomic chains bonded ionically or covalently in one direction and held together by van der Waals interactions in the perpendicular directions, have recently gained intensive attention due to their exceptional functions. In this work, we report the discovery of 1D ionic-bonded structures in NiSe nanowires. Utilizing aberration-corrected scanning transmission electron microscopy, we identified four distinct structural phases composed of two fundamental 1D building blocks: a triangle-shaped unit and a parallelogram-shaped unit. These phases can transform into one another through topotactic combinations of the structural units. Density functional theory calculations reveal that these structural units are bound by ionic bonds, unlike the van der Waals forces typically found in 1D vdW materials. The diverse arrangements of these building blocks may give rise to unique electronic structures and magnetic properties, paving the way for designing advanced materials with novel functionalities.