# Alkali-Metal Interlocking of 2D V4O10 Sheets Defines Discretized Interlayer Shear Relationships

## TL;DR

This paper explores how alkali-metal ions influence the structure and magnetic properties of layered vanadium oxide sheets.

## Contribution

The study identifies seven coordination sites and four shear regimes for alkali-metal intercalation in vanadium oxide.

## Key findings

- Alkali-metal intercalation leads to four distinct interlayer shear regimes.
- Coordination preferences of cations govern sheet interlocking and shear conformations.
- Static and dynamic disorder modulates magnetic structures via electrostatic and spin effects.

## Abstract

Low-dimensional materials manifest structural anisotropy,
quantum
confinement, and tightly bound excitonic states, which make them attractive
building blocks that can be assembled within three-dimensional laterally
stitched heterostructures, stacked van der Waals solids, and complex
moiré superlattices. Ion intercalation in the galleries between
layered materials provides a means of modifying interlayer separation
and coupling, but it is also known to drive the shearing of the layers.
In this article, we explore the distinct ligand coordination environments
afforded by vanadyl oxygens of singular [V4O10] sheets and examine how the size, polarizability, and stoichiometry
of Group I cations sandwiched between such layers determine the interlocking
of the sheets in stacked structures. Based on the topochemical insertion
of alkali-metal ions into the layered λ-V2O5, we identify seven types of guest ion coordination sites discretized
into four distinct regimes of interlayer shear in units of half octahedral
widths. The coordination preferences of intercalated cations govern
how they interlock 2D [V4O10] sheets and engender
specific shear conformations. We present evidence that static and
dynamic disorder in guest ion arrangement modulate the magnetic structure
of the intercalated compounds based on electrostatic polarization,
localization of charge and spin density, and lattice distortion. The
results illustrate the use of topochemical ion insertion to modulate
stacking relationships and magnetic transition characteristics.