Rotating lattice single crystal architecture on the surface of glass

Abstract

Defying the requirements of translational periodicity in 3D, rotation of the lattice orientation within an otherwise single crystal provides a new form of solid. Such rotating lattice single (RLS) crystals are found, but only as spherulitic grains too small for systematic characterization or practical application. Here we report a novel approach to fabricate RLS crystal lines and 2D layers of unlimited dimensions via a recently discovered solid-to-solid conversion process using a laser to heat a glass to its crystallization temperature but keeping it below the melting temperature. The proof-of-concept including key characteristics of RLS crystals is demonstrated using the example of Sb2S3 crystals within the Sb-S-I model glass system for which the rotation rate depends on the direction of laser scanning relative to the orientation of initially formed seed. Lattice rotation in this new mode of crystal growth occurs upon crystallization through a well-organized dislocation/disclination structure introduced at the glass/crystal interface. Implications of RLS growth on biomineralization and spherulitic crystal growth are noted.

Laser Fabrication of Two-Dimensional Rotating-Lattice Single Crystal

“…The diffraction from the scanned line of 2D laserwritten crystal, for instance, point #1 on Figure 10a shows a Laue spot that is steadily elongated with a rod-like intensity distribution (Figure 10c). Similar µSXRD Laue magnified images comprising of uniaxially elongated streaks were observed previously for 1D RLS crystal lines 11 .…”

“…As noted previously 11 , the lattice of single crystal line formed on the surface of glass by laser-induced solid state glass → crystal 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 crystal architecture. Arrows on IPF map (c) describe the axis and direction of the lattice cell rotations.…”

“…An indication of lattice rotation in 2D single crystal was mentioned recently 11 , but its complete nature remains to be explored and understood. Toward this goal, our first task has been to determine if and how such a structure can be fabricated.…”

“…When the crystal is grown on the surface such as by heating with a CW laser, the stress is anisotropic. Consequently, the lattice of the single crystal lines 'written' on the surface of glass has unique structure, exhibiting gradual rotation of crystal orientation 11 . For example, the orientation of unit cell of the single crystal line of Sb 2 S 3 fabricated by CW laser heating on the surface of an Sb-S-I glass gradually changes as one moves along the laser scanning direction.…”

“…Such a laser-written line constitutes a special form of single crystals, which have been labeled as 'rotating lattice single' (RLS) crystals 11 . An RLS crystal has translational periodicity of a unit cell but only in one direction, which is normal to the laser scan direction and parallel to glass surface.…”