Fig. 7: Regeneration of strained COM crystals.

a Step advancement as a function of time monitored by in situ AFM, as schematically illustrated in the insets with orange indicating growth and grey indicating growth suppression. Left axis: steps advancing in the [001] direction in the absence of modifier. Right axis: islands advancing in the [00\(\bar{1}\)] direction during regeneration after exposure to HMP. b ToF-SIMS intensity profiles of phosphate (PO_x) as a function of sputtering time. Samples were prepared by subjecting COM crystals to a sequence of treatments: (1) growth in a supersaturated solution without modifier for 2 h (control, gray); (2) growth in the same solution containing 1 μg mL⁻¹ modifier for 1 h; and (3) regeneration for 2 h in a supersaturated solution without modifier. The control is the baseline for comparing samples exposed to LTPP (yellow), HMP (red), and PA (orange). The blue shaded transient region (0–6 sec) represents the first monolayers that do not reflect PO_x absorption. c Temporal evolution in the cross-sectional area of COM crystals within microchannels during a period of growth in the absence of modifier (grey circles) following by regeneration after an initial exposure to HMP (blue squares and triangles) and PA (red diamonds). Optical micrographs of COM crystals during (d) control growth and e, f two separate regeneration tests after crystals are first exposed to HMP (see also Supplementary Movie 4 and Supplementary Fig. 20). Scale bars equal 20 μm. g, h SEM images of crystals regenerated for 12 h after exposure to 1 μg mL⁻¹ HMP. Recovered growth produces distinct morphological features that include protrusions, new crystals nucleating at apical tips and basal surfaces, and overlayers that partially encompass the original crystal. Scale bars equal 5 μm.