Fig. 4: Elastic deformation of reticular nano-spring structures.

a Schematic of the nano-spring structure with a central disk and surrounding concentric arcs (reticular nano-spring), and the reversible probe landing scheme. b SEM images of two structures under the deformation process. The width of Web-6 and Web-8 structures are 6 and 8 µm, respectively, while the diameters of central disks are both at 3 µm. c Stress distribution diagrams of Web-6 and Web-8 structures with deformation height of 1.25 μm, corresponding to maximum strain values of 9.04% and 3.78%, respectively. d Recorded force applied onto the central disk versus time when the probe pushes the structure first, touches the substrate, and retracts backward at a constant speed of 10 nm/s. e Measured (dotted lines, with minimum response force of 10 nN) and calculated (thick gray lines) force versus the vertical displacement of the central disk, showing high consistency. The inset illustrates a simplified nano-spring model of the web structures, which is valid in the small-deformation region (solid lines). f SEM image of a reticular structure with a central disk diameter of 10 µm and overall width of 18 µm. g Schematic of the electromechanical reconfiguration of the reticular structure in (f). h Measured reflected intensity versus time at wavelength 732 nm when an alternative voltage of 200 Hz is applied on the reticular structure in (f). Scale bars: 1 µm.