02203nas a2200241   4500008004100000245009800041210006900139260000800208300000900216490000700225520141400232100001801646700002101664700002201685700002001707700001701727700001701744700001701761700002301778700001801801700001701819856012501836       2026                        eng d00aFast self-healing in a layered molecular crystal mediated by stress-induced symmetry breaking0 aFast selfhealing in a layered molecular crystal mediated by stre  cFEB  a25250 v173 a<p>
	In recent years, symmetry-breaking has emerged as a powerful tool for significantly altering various physical properties in 2D layered materials. However, the breaking of symmetry by means of mechanical stress in organic crystals remains elusive. Here, we demonstrate a simple approach to engineer symmetry-breaking through mechanical stress fields in a layered molecular crystal, resulting in autonomous and fast self-healing under ambient temperature and pressure conditions. Fracture mechanics analysis reveals that the crystal adheres to an elasto-plastic model, with formation of a plastic zone at the crack tip, which prevents further crack propagation, facilitating the self-healing process. Spatially resolved Raman mapping reveals that the crack formation is accompanied by a distinct symmetry-breaking mechanism at the microstructural level. A six-fold increase in non-linear second harmonic (SH) activity, triggered by mechanical perturbation, further validates the local symmetry breaking in an otherwise centrosymmetric crystal. Furthermore, symmetry is restored following successful healing, as evidenced by the disappearance of the SH signal in the healed regions. This study not only broadens the scope of self-healing mechanisms viable in molecular materials but also offers key insights into the role of symmetry breaking and its potential for related technological applications.</p>
1 aGhosh, Ishita1 aBiswas, Rabindra1 aTanwar, Manushree1 aBhunia, Surojit1 aDas, Kaustav1 aTorris, Arun1 aMondal, Amit1 aRaghunathan, Varun1 aKumar, Rajesh1 aReddy, Malla  uhttps://library.ncl.res.in/content/fast-self-healing-layered-molecular-crystal-mediated-stress-induced-symmetry-breaking