Establishing Nanoscale Heterogeneity with Nanoscale Force Measurements

Establishing the presence or absence of nanoscale compositional heterogeneity with nanoscale resolution is becoming instrumental for the development of many fields of science. Force versus distance measurements and parameters directly or indirectly derived from these profiles can be potentially employed for this purpose with sophisticated instruments such as the atomic force microscope (AFM). On the other hand, standards are necessary to reproducibly and conclusively support hypothesis from experimental data and these standards are still emerging. Here, we define a set of standards for providing data originating from atomic force measurements to be employed to compare between sample properties, parameters, or, more generally, compositional heterogeneity. We show that reporting the mean and standard deviation only might lead to inconsistent conclusions. The fundamental principle behind our investigation deals with the very definition of reproducibility and repeatability in terms of accuracy and precision, and we establish general criteria to ensure that these hold without the need of restricting assumptions.