Exfoliation and Cleavage of Crystals from a Universal Potential

TL;DR

This paper introduces a universal computational framework for predicting exfoliable 2D materials from bulk crystals, significantly expanding the potential for discovering novel low-dimensional materials beyond van der Waals systems.

Contribution

A novel universal exfoliation and cleavage potential (XCP) model enabling large-scale, cost-effective screening of diverse crystal structures for 2D material exfoliation.

Findings

Identified 37,208 cleavable surfaces and candidate 2D materials.

Discovered 2,377 likely exfoliable non-vdW 2D materials.

Found new 2D metals and semiconductors with unique electronic properties.

Abstract

Exfoliation and cleavage create two-dimensional (2D) materials and surfaces with physical and chemical properties distinct from their bulk parents. The rising class of non-van der Waals (non-vdW) 2D materials derived from non-layered crystals provides a fascinating new platform - greatly expanding the landscape of low-dimensional materials. Current computational models, however, provide limited guidance: existing descriptors are largely tailored to vdW layered systems. Here, we introduce a general framework predicting crystal cleavage and exfoliable 2D subunits directly from bulk structures. At its core is a universal eXfoliation and Cleavage Potential (XCP) enabling large-scale screening of diverse materials at negligible computational cost. Applying this approach, we obtain 37,208 cleavable surfaces and candidate non-vdW 2D materials from which we investigate 2,377 likely exfoliable ones using high-throughput density functional theory. We identify sheets with square and rectangular lattices, semiconducting systems exhibiting an indirect-to-direct band-gap transition upon exfoliation, and first non-vdW 2D metals. Our study thus opens a systematic route to explore and design new 2D materials with unprecedented chemical and structural diversity.