Intrinsic Fracture Nonreciprocity at the Nanoscale

TL;DR

This paper uncovers intrinsic fracture nonreciprocity in 2D heterostructures caused by lattice mismatch, revealing a universal exponential failure law and demonstrating how interface strain engineering can enhance nanoscale damage tolerance.

Contribution

It introduces the concept of intrinsic fracture nonreciprocity driven by lattice mismatch and establishes a universal failure criterion linking charge density and bond strain.

Findings

Nonreciprocal crack resistance scales with lattice mismatch, reaching 49% at 10% mismatch.

Universal exponential law relates charge density and bond strain, independent of chemistry.

Validation across various 2D lattice types confirms the universality of the phenomenon.

Abstract

We reveal intrinsic fracture nonreciprocity, manifesting as directional asymmetry in crack resistance, in two-dimensional heterostructures engineered through lattice-mismatched interfaces. Density-functional theory combined with machine-learning molecular dynamics show that intrinsic lattice mismatch between bonded component crystals imprints asymmetric prestrain states at crack tips, governing bond-breaking thresholds through charge redistribution. The failure criterion obeys a universal exponential scaling law between normalized charge density and bond strain, insensitive to bonding chemistry and local atomic environment. The magnitude of nonreciprocity scales systematically with lattice mismatch, reaching 49% at 10% mismatch. Validation across hexagonal, square, rectangular, and oblique two-dimensional lattices confirms universality, establishing interface strain engineering as a general design principle that bridges electronic structure to nanoscale failure, enabling rational design of damage-tolerant nanostructures.