title: Pre-yield non-affine fluctuations and a hidden critical point in strained crystals.
abstract: A crystalline solid exhibits thermally induced localised non-affine droplets in the absence of external stress. Here we show that upon an imposed shear, the size of these droplets grow until they percolate at a critical strain, well below the value at which the solid begins to yield. This critical point does not manifest in most thermodynamic or mechanical properties, but is hidden and reveals itself in the onset of inhomogeneities in elastic moduli, marked changes in the appearance and local properties of non-affine droplets and a sudden enhancement in defect pair concentration. Slow relaxation of stress and an-elasticity appear as observable dynamical consequences of this hidden criticality. Our results may be directly verified in colloidal crystals with video microscopy techniques but are expected to have more general validity.
authors.affiliation: 1] Collective Interactions Unit, OIST Graduate University,1919-1 Tancha, Onna-son, Okinawa. 904-0495, Japan [2] Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Tamoghna
authors.initials: T
authors.lastname: Das
authors.affiliation: Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Saswati
authors.initials: S
authors.lastname: Ganguly
authors.affiliation: TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500075, India.
authors.forename: Surajit
authors.initials: S
authors.lastname: Sengupta
authors.affiliation: 1] Raman Research Institute, C.V. Raman Avenue, Bangalore 560080, India [2] National Centre for Biological Sciences (TIFR), Bellary Road, Bangalore 560065, India.
authors.forename: Madan
authors.initials: M
authors.lastname: Rao