With the invention of scanning tunneling microscopy (STM) and atomic force microscopy (AFM)1,2, researchers started to see atomic structure and manipulate atoms and molecules using nanoscale metallic or silicon tips in both vacuum and ambient conditions3,4. As AFM can detect tiny displacement of the cantilever (< 10 pm) in contact or proximity with the materials surface, any physical parameters coupled with strain could be used to image relevant order parameters (for example, polarization5, magnetization6, and ionic concentration7). Furthermore, conducting AFM opened up local current measurement in conjunction with external stimuli such as heat and photons8, which could be used to detect photovoltaic effect at the nanoscale9.

           As imaging consists of positioning, encoding and decoding of measured data and transducing one form of energy into another, any breakthrough in imaging technology can lead to a new design in information storage devices, imaging sensors or energy storage and harvesting devices10. Consequently, the inventors of SPM have been deeply involved in innovative probe-based data storage devices (e.g., IBM ’ s millipede project), where multiple nanoscale tips read and write data on the thin film surface in microelectromechanical system (MEMS)11,12.

Figure 1. Schematic diagram of scanning resistive probe microscopy. Reprinted with permission from Ref [15]. Copyright 2011, American Chemical Society.